Physical Activity, Moderate Alcohol Intake Associated with Improved Survival
Physical activity and moderate alcohol consumption may help reduce fatal ischemic heart disease (IHD) and all-cause mortality, reports the European Heart Journal.
Nearly 12,000 Danish adults without previous IHD reported their alcohol intake and physical activity level and then were followed for about 20 years. Overall, about half died, with IHD accounting for 20% of the deaths.
After adjustment for confounders such as age and smoking status, active subjects had lower risks for fatal IHD and all-cause mortality than inactive subjects, and moderate drinkers (1 to 14 drinks a week) had lower mortality risks than nondrinkers. A combination of physical activity and moderate drinking appeared most beneficial — active subjects who consumed at least one drink weekly had up to a 50% lower risk for fatal IHD and up to a 33% lower all-cause mortality risk.
European Heart Journal article (Free PDF)
Abstract:
The combined influence of leisure-time physical activity and weekly alcohol intake on fatal ischaemic heart disease and all-cause mortality
Aims
To determine the combined influence of leisure-time physical activity and weekly alcohol intake on the risk of subsequent fatal ischaemic heart disease (IHD) and all-cause mortality.
Methods and results
Prospective cohort study of 11 914 Danes aged 20 years or older and without pre-existing IHD. During _20 years of follow-up, 1242 cases of fatal IHD occurred and 5901 died from all causes. Within both genders, being physically active was associated with lower hazard ratios (HR) of both fatal IHD and all-cause mortality than being physically inactive. Further, weekly alcohol intake was inversely associated with fatal IHD and had a U-shaped association with all-cause mortality. Within level of physical activity, non-drinkers had the highest HR of fatal IHD, whereas both non-drinkers and heavy drinkers had the highest HR of all-cause mortality. Further, the physically inactive had the highest HR of both fatal IHD and all-cause mortality within each category of weekly alcohol intake. Thus, the HR of both fatal IHD and all-cause mortality were low among the physically active who had a moderate alcohol intake.
Conclusion
Leisure-time physical activity and a moderate weekly alcohol intake are both important to lower the risk of fatal IHD and all-cause mortality.
Showing posts with label Physical Activity. Show all posts
Showing posts with label Physical Activity. Show all posts
Wednesday, January 9, 2008
Wednesday, November 21, 2007
Regular Exercise Reduces Risk Of Blood Clots
Regular Exercise Reduces Risk Of Blood Clots
21 Nov 2007
According to a new study published in Journal of Thrombosis and Haemostasis, regular participation in sports reduces the risk of developing blood clots by 39 percent in women and 22 percent in men.
Researchers from Leiden University Medical Center in the Netherlands evaluated 7,860 people aged 18-70. Patients who had suffered their first blood clot in a leg vein or lung artery were compared with control subjects who had never experienced blood clots. 31 percent of the patients and 40 percent of the control group participated in sports on a regular basis.
Overall figures for both sexes showed that participating in sports at least once per week, regardless of the type of sport or its intensity, reduced the risk of developing a blood clot in a lung artery by 46 percent and a blood clot in a leg vein by 24 percent. "Women were shown to be even more likely to reap the benefits of regular sporting activities than men," says F.R. Rosendaal, co-author of the study. "When we excluded women who were pregnant or receiving oral contraceptive or hormone replacement therapy - all possible causes of blood clots - the risk for women was reduced by 55 percent."
The authors note that, while strenuous activity is known to increase the risk of blood clot development in the elderly, regular exercise is also shown to greatly benefit the heart, and that the net effect of elderly sports participation may be positive.
The findings also show that people who did not participate in sports were more than four-times as likely to develop a blood clot if they were obese (with a body mass index of 30 or greater) than lean (with a body mass index of less than 25). "When we looked at the results, we found that, overall, the mere fact that people took part in a sporting activity at least once a week was enough to lower their risk of blood clots," say the authors.
Article adapted by Medical News Today from original press release.
21 Nov 2007
According to a new study published in Journal of Thrombosis and Haemostasis, regular participation in sports reduces the risk of developing blood clots by 39 percent in women and 22 percent in men.
Researchers from Leiden University Medical Center in the Netherlands evaluated 7,860 people aged 18-70. Patients who had suffered their first blood clot in a leg vein or lung artery were compared with control subjects who had never experienced blood clots. 31 percent of the patients and 40 percent of the control group participated in sports on a regular basis.
Overall figures for both sexes showed that participating in sports at least once per week, regardless of the type of sport or its intensity, reduced the risk of developing a blood clot in a lung artery by 46 percent and a blood clot in a leg vein by 24 percent. "Women were shown to be even more likely to reap the benefits of regular sporting activities than men," says F.R. Rosendaal, co-author of the study. "When we excluded women who were pregnant or receiving oral contraceptive or hormone replacement therapy - all possible causes of blood clots - the risk for women was reduced by 55 percent."
The authors note that, while strenuous activity is known to increase the risk of blood clot development in the elderly, regular exercise is also shown to greatly benefit the heart, and that the net effect of elderly sports participation may be positive.
The findings also show that people who did not participate in sports were more than four-times as likely to develop a blood clot if they were obese (with a body mass index of 30 or greater) than lean (with a body mass index of less than 25). "When we looked at the results, we found that, overall, the mere fact that people took part in a sporting activity at least once a week was enough to lower their risk of blood clots," say the authors.
Article adapted by Medical News Today from original press release.
Monday, October 1, 2007
Physical Activity and Public Health in Older Adults: Recommendation From the American College of Sports Medicine and the American Heart Association
Title: Physical Activity and Public Health in Older Adults: Recommendation From the American College of Sports Medicine and the American Heart Association
Date Posted: 9/26/2007
Author(s): Nelson ME, Rejeski WJ, Blair SN, et al.
Citation: Circulation. 2007;116:1094-1105.
Perspective: The following are 10 points to remember about this recommendation on physical activity and public health in older adults:
1. Benefits of regular physical activity include reductions in the risk of diabetes, hypertension, cardiovascular disease (including stroke), dyslipidemia, obesity, anxiety, and depression. Physical activity is a component of clinical practice guidelines for coronary heart disease, hypertension, peripheral vascular disease, diabetes, obesity, and hyperlipidemia. Currently, older Americans are the least fit of any age group. In a study of Medicare enrollees, an estimated 14% of the men and 23% of the women were not able to walk 2-3 blocks. This age group is the fastest growing demographic segment in the United States, and has significant medical expenditures. Therefore, increasing physical activity among older adults has significant public health implications.
2. Physical activity recommendations for older adults pertain to all adults ages 65 or older, and to those ages 50-64 years with clinically significant chronic conditions and/or functional limitations. Recommendations are similar to those for adults under 65 years of age; however, intensity recommendations have been adapted to accommodate a wide range of aerobic fitness levels.
3. Physical activity recommendations include a minimum of 30 minutes/day of moderate intensity activity 5 days per week or a minimum of 20 minutes/day of vigorous activity 3 days/week. Moderate intensity activity can be completed in 10-minute intervals throughout the day. On a 10-point scale, moderate intensity is a 5-6 of perceived effort, whereas vigorous activity is a 7-8.
4. The intensity level for older adults is relative to the individual’s aerobic fitness and thus varies by person. These amounts of aerobic activity recommended should be in addition to routine daily activities such as cooking or shopping.
5. If conditions or baseline fitness do not permit the patient to achieve minimum levels of recommended physical activity, older adults should maintain regular physical activity consistent with their abilities and avoid sedentary behavior.
6. Benefits of physical activity appear to have a dose-response relationship, such that reductions in the risk of cardiovascular disease have been observed with as little as 45-75 minutes per week of walking.
7. Muscle strengthening activities are recommended at least 2 times per week and should include 8-10 exercises, which involve major muscle groups (with 10-15 repetitions). For those older adults at increased risk for falls, flexibility and balances exercises should be incorporated into these activities.
8. Physical activity has been observed to reduce risk of falls (and fall injuries) by as much a 35%-40%. Several studies have noted balance exercises to be an effective component of fall prevention.
9. An activity plan for an older adult should tailor recommendations to the person’s abilities and conditions and should include a stepwise plan for gradual increases in physical activity to achieve recommended levels of physical activity.
10. The majority of older Americans should be physically active. Both individual and community interventions are needed to support current recommendations for older adults, particularly in light of the growing number of older men and women residing in the United States.
Elizabeth A. Jackson, M.D., F.A.C.C.
Date Posted: 9/26/2007
Author(s): Nelson ME, Rejeski WJ, Blair SN, et al.
Citation: Circulation. 2007;116:1094-1105.
Perspective: The following are 10 points to remember about this recommendation on physical activity and public health in older adults:
1. Benefits of regular physical activity include reductions in the risk of diabetes, hypertension, cardiovascular disease (including stroke), dyslipidemia, obesity, anxiety, and depression. Physical activity is a component of clinical practice guidelines for coronary heart disease, hypertension, peripheral vascular disease, diabetes, obesity, and hyperlipidemia. Currently, older Americans are the least fit of any age group. In a study of Medicare enrollees, an estimated 14% of the men and 23% of the women were not able to walk 2-3 blocks. This age group is the fastest growing demographic segment in the United States, and has significant medical expenditures. Therefore, increasing physical activity among older adults has significant public health implications.
2. Physical activity recommendations for older adults pertain to all adults ages 65 or older, and to those ages 50-64 years with clinically significant chronic conditions and/or functional limitations. Recommendations are similar to those for adults under 65 years of age; however, intensity recommendations have been adapted to accommodate a wide range of aerobic fitness levels.
3. Physical activity recommendations include a minimum of 30 minutes/day of moderate intensity activity 5 days per week or a minimum of 20 minutes/day of vigorous activity 3 days/week. Moderate intensity activity can be completed in 10-minute intervals throughout the day. On a 10-point scale, moderate intensity is a 5-6 of perceived effort, whereas vigorous activity is a 7-8.
4. The intensity level for older adults is relative to the individual’s aerobic fitness and thus varies by person. These amounts of aerobic activity recommended should be in addition to routine daily activities such as cooking or shopping.
5. If conditions or baseline fitness do not permit the patient to achieve minimum levels of recommended physical activity, older adults should maintain regular physical activity consistent with their abilities and avoid sedentary behavior.
6. Benefits of physical activity appear to have a dose-response relationship, such that reductions in the risk of cardiovascular disease have been observed with as little as 45-75 minutes per week of walking.
7. Muscle strengthening activities are recommended at least 2 times per week and should include 8-10 exercises, which involve major muscle groups (with 10-15 repetitions). For those older adults at increased risk for falls, flexibility and balances exercises should be incorporated into these activities.
8. Physical activity has been observed to reduce risk of falls (and fall injuries) by as much a 35%-40%. Several studies have noted balance exercises to be an effective component of fall prevention.
9. An activity plan for an older adult should tailor recommendations to the person’s abilities and conditions and should include a stepwise plan for gradual increases in physical activity to achieve recommended levels of physical activity.
10. The majority of older Americans should be physically active. Both individual and community interventions are needed to support current recommendations for older adults, particularly in light of the growing number of older men and women residing in the United States.
Elizabeth A. Jackson, M.D., F.A.C.C.
Tuesday, September 18, 2007
Aerobic, Resistance Training Improve Glycemic Control in Type 2 Diabetes
Aerobic, Resistance Training Improve Glycemic Control in Type 2 Diabetes
Both aerobic and resistance training help lower hemoglobin A1c levels in patients with type 2 diabetes — and a combination of the two is even more beneficial — researchers report in Annals of Internal Medicine.
Some 250 inactive diabetes patients were randomized to one of four groups: aerobic training, resistance training, both, or no exercise. The active-treatment groups exercised 3 times weekly for 22 weeks.
Adjusted absolute HbA1c levels fell significantly with aerobic training (-0.51 percentage point vs. no exercise) and resistance training (-0.38); the combination-exercise group saw additional reductions (-0.46 vs. aerobic training, -0.59 vs. resistance training). Changes in blood pressure and lipids did not differ among the groups.
The authors cite research showing a 15% to 20% reduction in major cardiovascular events with a 1-percentage-point decrease in HbA1c. Editorialists note limitations of the current study but conclude: "Failing to prescribe exercise to patients with diabetes is simply unacceptable practice."
Annals of Internal Medicine article (Free)
Annals of Internal Medicine editorial (Subscription required)
Both aerobic and resistance training help lower hemoglobin A1c levels in patients with type 2 diabetes — and a combination of the two is even more beneficial — researchers report in Annals of Internal Medicine.
Some 250 inactive diabetes patients were randomized to one of four groups: aerobic training, resistance training, both, or no exercise. The active-treatment groups exercised 3 times weekly for 22 weeks.
Adjusted absolute HbA1c levels fell significantly with aerobic training (-0.51 percentage point vs. no exercise) and resistance training (-0.38); the combination-exercise group saw additional reductions (-0.46 vs. aerobic training, -0.59 vs. resistance training). Changes in blood pressure and lipids did not differ among the groups.
The authors cite research showing a 15% to 20% reduction in major cardiovascular events with a 1-percentage-point decrease in HbA1c. Editorialists note limitations of the current study but conclude: "Failing to prescribe exercise to patients with diabetes is simply unacceptable practice."
Annals of Internal Medicine article (Free)
Annals of Internal Medicine editorial (Subscription required)
Monday, August 13, 2007
Moderate Exercise Might Be Healthier Than Intense Workouts
Moderate Exercise Might Be Healthier Than Intense Workouts
Just a 30-minute daily walk can help stave off diabetes, heart trouble, study finds
FRIDAY, Aug. 10 (HealthDay News) --
Moderate exercise, such as walking 30 minutes a day, may offer better protection against diabetes and heart disease than a more rigorous workout regimen, concludes a U.S. study that included 240 middle-age, sedentary people.
"On the surface, it seems to make sense that the harder we exercise, the better off we'll be, and by some measures that's true," lead author and exercise physiologist Cris Slentz, of Duke University Medical Center, said in a prepared statement. "But our studies show that a modest amount of moderately intense exercise is the best way to significantly lower the level of a key blood marker linked to higher risk of heart disease and diabetes. More intense exercise doesn't seem to do that."
Perhaps even more surprising is that some of the benefits achieved through moderate exercise seem to last much longer than the benefits gained through more intense training, Slentz said.
The study was published in the August issue of the Journal of Applied Physiology.
The participants in the study were divided into four exercise groups: high amount/high intensity; low amount/high intensity; low amount/moderate intensity; and a control group that did no exercise. The volunteers started with a two- to three-month "ramp-up" period and then continued their exercise programs for six months.
The Duke team found that no amount of exercise significantly changed levels of low- density lipoprotein (LDL -- "bad" cholesterol). However, length and intensity of exercise did improve levels of high-density lipoprotein (HDL -- "good" cholesterol), and that benefit was sustained over time.
The study also found that low amount/moderate intensity exercise significantly lowered levels of triglycerides, which are particles that carry fat around the body and are also a good indicator of insulin resistance, a marker for diabetes. Reducing triglyceride levels lowers a person's risk of diabetes and heart disease.
"A proper exercise program appears to be able to lower a person's insulin resistance in just a matter of days. We were also amazed to see that the lower triglyceride levels stayed low even two weeks after the workouts ended," senior author and cardiologist Dr. William Kraus said in a prepared statement.
Just a 30-minute daily walk can help stave off diabetes, heart trouble, study finds
FRIDAY, Aug. 10 (HealthDay News) --
Moderate exercise, such as walking 30 minutes a day, may offer better protection against diabetes and heart disease than a more rigorous workout regimen, concludes a U.S. study that included 240 middle-age, sedentary people.
"On the surface, it seems to make sense that the harder we exercise, the better off we'll be, and by some measures that's true," lead author and exercise physiologist Cris Slentz, of Duke University Medical Center, said in a prepared statement. "But our studies show that a modest amount of moderately intense exercise is the best way to significantly lower the level of a key blood marker linked to higher risk of heart disease and diabetes. More intense exercise doesn't seem to do that."
Perhaps even more surprising is that some of the benefits achieved through moderate exercise seem to last much longer than the benefits gained through more intense training, Slentz said.
The study was published in the August issue of the Journal of Applied Physiology.
The participants in the study were divided into four exercise groups: high amount/high intensity; low amount/high intensity; low amount/moderate intensity; and a control group that did no exercise. The volunteers started with a two- to three-month "ramp-up" period and then continued their exercise programs for six months.
The Duke team found that no amount of exercise significantly changed levels of low- density lipoprotein (LDL -- "bad" cholesterol). However, length and intensity of exercise did improve levels of high-density lipoprotein (HDL -- "good" cholesterol), and that benefit was sustained over time.
The study also found that low amount/moderate intensity exercise significantly lowered levels of triglycerides, which are particles that carry fat around the body and are also a good indicator of insulin resistance, a marker for diabetes. Reducing triglyceride levels lowers a person's risk of diabetes and heart disease.
"A proper exercise program appears to be able to lower a person's insulin resistance in just a matter of days. We were also amazed to see that the lower triglyceride levels stayed low even two weeks after the workouts ended," senior author and cardiologist Dr. William Kraus said in a prepared statement.
Thursday, May 17, 2007
Even low-level physical activity improves the cardiorespiratory fitness
Effects of Different Doses of Physical Activity on Cardiorespiratory Fitness Among Sedentary, Overweight or Obese Postmenopausal Women With Elevated Blood Pressure
A Randomized Controlled Trial
Timothy S. Church, MD, MPH, PhD; Conrad P. Earnest, PhD; James S. Skinner, PhD; Steven N. Blair, PED
JAMA. 2007;297:2081-2091.
Context Low levels of cardiorespiratory fitness are associated with high risk of mortality, and improvements in fitness are associated with reduced mortality risk. However, a poor understanding of the physical activity–fitness dose response relation remains.
Objective To examine the effect of 50%, 100%, and 150% of the NIH Consensus Development Panel recommended physical activity dose on fitness in women.
Design, Setting, and Participants Randomized controlled trial of 464 sedentary, postmenopausal overweight or obese women whose body mass index ranged from 25.0 to 43.0 and whose systolic blood pressure ranged from 120.0 to 159.9 mm Hg. Enrollment took place between April 2001 and June 2005 in the Dallas, Tex, area.
Intervention Participants were randomly assigned to 1 of 4 groups: 102 to the nonexercise control group and 155 to the 4-kcal/kg, 104 to the 8-kcal/kg, and 103 to the 12-kcal/kg per week energy-expenditure groups for the 6-month intervention period. Target training intensity was the heart rate associated with 50% of each woman's peak O2.
Main Outcome Measure The primary outcome was aerobic fitness assessed on a cycle ergometer and quantified as peak absolute oxygen consumption ( O2abs, L/min).
Results The mean (SD) baseline O2abs values were 1.30 (0.25) L/min. The mean (SD) minutes of exercising per week were 72.2 (12.3) for the 4-kcal/kg, 135.8 (19.5) for the 8-kcal/kg, and 191.7 (33.7) for the 12-kcal/kg per week exercise groups. After adjustment for age, race/ethnicity, weight, and peak heart rate, the exercise groups increased their O2abs compared with the control group by 4.2% in the 4-kcal/kg, 6.0% in the 8-kcal/kg, and 8.2% in the 12-kcal/kg per week groups (P<.001 for each vs control; P for trend <.001). There was no treatment x subgroup interaction for age, body mass index, weight, baseline O2abs, race/ethnicity, or baseline hormone therapy use. There were no significant changes in systolic or diastolic blood pressure values from baseline to 6 months in any of the exercise groups vs the control group. Conclusion In this study, previously sedentary, overweight or obese postmenopausal women experienced a graded dose-response change in fitness across levels of exercise training.
COMMENTARIES Even small doses of activity boost heart fitness 16 May 2007 MedWire News: Even low-level physical activity improves the cardiorespiratory fitness of overweight, sedentary individuals, study findings reveal.
National Institutes of Health (NIH) guidelines recommend at least 30 minutes of moderate-intensity physical activity to promote general health, but it is not clear if sedentary people will benefit from lower levels of activity than this, explain Timothy Church (Louisiana State University System, Baton Rouge, USA) and colleagues.
To investigate, the researchers conducted a study in 464 sedentary, postmenopausal overweight or obese women with elevated blood pressure.
The women’s body mass indices ranged from 25.0 to 43.0 and systolic blood pressure from 120.0 to 159.9 mmHg.
The participants were randomly assigned to three different levels of exercise or to a no-exercise control group. The three exercise levels were cycling or walking sessions designed to expend 4 kcal/kg, 8kcal/kg, or 12 kcal/kg per week.
These levels corresponded to 50%, 100%, and 150% of the NIH consensus recommended activity level for such women.
Women who exercised participated in three or four training sessions each week for 6 months, at a training intensity of the heart rate associated with 50% peak oxygen consumption (VO2). Although maximal effort was obtained during exercise testing, the mean peak absolute (VO2abs) and relative (VO2rel) values were very low, at 1.30 l/min and 15.5 ml/kg/min, respectively, at baseline.
This demonstrated that the group had very low fitness levels at the start of the study, the authors note.
The 4-kcal/kg group exercised for a mean of 72.2 minutes per week over 2.6 sessions, the 8-kcal/kg group for 135.8 minutes per week during 2.8 sessions, and the 12-kcal/kg group for 191.7 minutes per week during 3.1 sessions.
There was a strong dose-response relationship between the amount of exercise and change in fitness, Church and team report in the Journal of the American Medical Association.
Peak absolute oxygen consumption VO2abs were significantly increased at all three exercise levels versus no exercise (1.33, 1.35, and 1.39 vs 1.28 l/min).
These values represented a 4.2% increase in VO2abs in the 4-kcal/kg group, a 6.0% increase in 8-kcal/kg group, and an 8.2% increase in the 12-kcal/kg group, compared with the control no-exercise group (all p<0.001 versus control; p for trend <0.001).
The dose-response relationship was seen across age, race, weight, baseline fitness, and hormone therapy subgroups.
Participants’ systolic and diastolic blood pressure levels, weight, and most other cardiovascular risk factors were not significantly altered with any level of exercise.
However, waist circumference, which was similar in each group at baseline, was significantly reduced at the end of the study in all 3 exercise groups compared with the control group (p<0.05 for each).
This was a significant finding given the importance of increased risk of insulin resistance, diabetes, and metabolic syndrome, and mortality associated with abdominal obesity, Church and team emphasize.
“Perhaps the most striking finding of our study is that even activity at the 4-kcal/kg per week level (approximately 72 min per week) was associated with a significant improvement in fitness compared with women in the nonexercise control group,” the team comments. JAMA 2007; 297: 2081-2091
A Randomized Controlled Trial
Timothy S. Church, MD, MPH, PhD; Conrad P. Earnest, PhD; James S. Skinner, PhD; Steven N. Blair, PED
JAMA. 2007;297:2081-2091.
Context Low levels of cardiorespiratory fitness are associated with high risk of mortality, and improvements in fitness are associated with reduced mortality risk. However, a poor understanding of the physical activity–fitness dose response relation remains.
Objective To examine the effect of 50%, 100%, and 150% of the NIH Consensus Development Panel recommended physical activity dose on fitness in women.
Design, Setting, and Participants Randomized controlled trial of 464 sedentary, postmenopausal overweight or obese women whose body mass index ranged from 25.0 to 43.0 and whose systolic blood pressure ranged from 120.0 to 159.9 mm Hg. Enrollment took place between April 2001 and June 2005 in the Dallas, Tex, area.
Intervention Participants were randomly assigned to 1 of 4 groups: 102 to the nonexercise control group and 155 to the 4-kcal/kg, 104 to the 8-kcal/kg, and 103 to the 12-kcal/kg per week energy-expenditure groups for the 6-month intervention period. Target training intensity was the heart rate associated with 50% of each woman's peak O2.
Main Outcome Measure The primary outcome was aerobic fitness assessed on a cycle ergometer and quantified as peak absolute oxygen consumption ( O2abs, L/min).
Results The mean (SD) baseline O2abs values were 1.30 (0.25) L/min. The mean (SD) minutes of exercising per week were 72.2 (12.3) for the 4-kcal/kg, 135.8 (19.5) for the 8-kcal/kg, and 191.7 (33.7) for the 12-kcal/kg per week exercise groups. After adjustment for age, race/ethnicity, weight, and peak heart rate, the exercise groups increased their O2abs compared with the control group by 4.2% in the 4-kcal/kg, 6.0% in the 8-kcal/kg, and 8.2% in the 12-kcal/kg per week groups (P<.001 for each vs control; P for trend <.001). There was no treatment x subgroup interaction for age, body mass index, weight, baseline O2abs, race/ethnicity, or baseline hormone therapy use. There were no significant changes in systolic or diastolic blood pressure values from baseline to 6 months in any of the exercise groups vs the control group. Conclusion In this study, previously sedentary, overweight or obese postmenopausal women experienced a graded dose-response change in fitness across levels of exercise training.
COMMENTARIES Even small doses of activity boost heart fitness 16 May 2007 MedWire News: Even low-level physical activity improves the cardiorespiratory fitness of overweight, sedentary individuals, study findings reveal.
National Institutes of Health (NIH) guidelines recommend at least 30 minutes of moderate-intensity physical activity to promote general health, but it is not clear if sedentary people will benefit from lower levels of activity than this, explain Timothy Church (Louisiana State University System, Baton Rouge, USA) and colleagues.
To investigate, the researchers conducted a study in 464 sedentary, postmenopausal overweight or obese women with elevated blood pressure.
The women’s body mass indices ranged from 25.0 to 43.0 and systolic blood pressure from 120.0 to 159.9 mmHg.
The participants were randomly assigned to three different levels of exercise or to a no-exercise control group. The three exercise levels were cycling or walking sessions designed to expend 4 kcal/kg, 8kcal/kg, or 12 kcal/kg per week.
These levels corresponded to 50%, 100%, and 150% of the NIH consensus recommended activity level for such women.
Women who exercised participated in three or four training sessions each week for 6 months, at a training intensity of the heart rate associated with 50% peak oxygen consumption (VO2). Although maximal effort was obtained during exercise testing, the mean peak absolute (VO2abs) and relative (VO2rel) values were very low, at 1.30 l/min and 15.5 ml/kg/min, respectively, at baseline.
This demonstrated that the group had very low fitness levels at the start of the study, the authors note.
The 4-kcal/kg group exercised for a mean of 72.2 minutes per week over 2.6 sessions, the 8-kcal/kg group for 135.8 minutes per week during 2.8 sessions, and the 12-kcal/kg group for 191.7 minutes per week during 3.1 sessions.
There was a strong dose-response relationship between the amount of exercise and change in fitness, Church and team report in the Journal of the American Medical Association.
Peak absolute oxygen consumption VO2abs were significantly increased at all three exercise levels versus no exercise (1.33, 1.35, and 1.39 vs 1.28 l/min).
These values represented a 4.2% increase in VO2abs in the 4-kcal/kg group, a 6.0% increase in 8-kcal/kg group, and an 8.2% increase in the 12-kcal/kg group, compared with the control no-exercise group (all p<0.001 versus control; p for trend <0.001).
The dose-response relationship was seen across age, race, weight, baseline fitness, and hormone therapy subgroups.
Participants’ systolic and diastolic blood pressure levels, weight, and most other cardiovascular risk factors were not significantly altered with any level of exercise.
However, waist circumference, which was similar in each group at baseline, was significantly reduced at the end of the study in all 3 exercise groups compared with the control group (p<0.05 for each).
This was a significant finding given the importance of increased risk of insulin resistance, diabetes, and metabolic syndrome, and mortality associated with abdominal obesity, Church and team emphasize.
“Perhaps the most striking finding of our study is that even activity at the 4-kcal/kg per week level (approximately 72 min per week) was associated with a significant improvement in fitness compared with women in the nonexercise control group,” the team comments. JAMA 2007; 297: 2081-2091
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