Exercise Boost HDL Cholesterol Levels

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Exercise May Slightly Boost 'Good' Cholesterol Levels

Science Daily — Regular exercise appears to modestly increase levels

of high-density lipoprotein, or " good, " cholesterol, according to a

meta-analysis study in the May 28 issue of Archives of Internal

Medicine, one of the JAMA/Archives journals.

A low level of high-density lipoprotein cholesterol (HDL-C) is an

independent risk factor for cardiovascular disease, the leading cause

of death worldwide, according to background information in the

article. There is strong evidence that individuals who are more

physically active have higher HDL-C levels. " Thus, the value of

regular aerobic exercise in increasing serum [blood] HDL-C level and

in reducing the risk of cardiovascular disease has received widespread

acceptance, " the authors write. " In contrast, results of aerobic

exercise studies vary considerably, depending on the exercise program

(e.g., duration, intensity or frequency) and characteristics of

subjects at baseline. "

Satoru Kodama, M.D., of Ochanomizu University, Tokyo, and colleagues

performed a meta-analysis of 25 articles reporting the results of

randomized controlled trials that were published between 1966 and 2005

and assessed the effects of exercise on HDL-C. To be included in the

analysis, the studies had to evaluate aerobic exercise in adults with

an average age of 20 or older, specify HDL-C measurements at the

beginning and end of the study, have a length of at least eight weeks,

and randomly assign some participants to a group of exercisers and

others to a control group of non-exercisers.

The 25 articles analyzed included a total of 1,404 participants with

an average age range of 23 to 75 years and an average study period of

27.4 weeks. The exercise groups were told to exercise for an average

of 3.7 sessions per week at an average of 40.5 minutes each, burning

an average of 1,019 calories per week.

In all the studies combined, HDL-C increased by an average of 2.53

milligrams per deciliter in the exercise groups. The minimum amount of

weekly exercise that appeared necessary to change HDL-C levels was 120

minutes or 900 calories burned. The effect of exercise was greater in

those who had a higher total cholesterol level (220 milligrams per

deciliter or greater) and in those with a body mass index of less than 28.

" In a previous observational study, every 1-milligram per deciliter

increment in HDL-C level was reported to be associated with a 2

percent and 3 percent decreased risk of cardiovascular disease in men

and women, respectively, " the authors write. " If this observation were

applied to our results, the increase in HDL-C level by exercise

determined by this analysis would, by a rough estimate, result in a

cardiovascular disease risk reduced by approximately 5.1 percent in

men and 7.6 percent in women. This is potentially of substantial

importance in public health, although the effect of reducing

cardiovascular risk by increasing HDL-C level might be smaller than

that by use of medications such as fibrates or niacin. "

Only exercise duration, and not frequency or intensity, was associated

with a change in HDL-C levels in the analysis. When the participants

exercised for 23 to 74 minutes per session, each 10-minute increase in

exercise duration corresponded to a 1.4-milligram per deciliter

increase in HDL-C level. " This suggests that in improving blood HDL-C

values, increasing time per session is better than performing multiple

brief exercise sessions when total time for exercise is limited, as is

the case for many people, " the authors write.

Reference:

Arch Intern Med. 2007 May 28;167(10):999-1008

Effect of Aerobic Exercise Training on Serum Levels of

High-Density Lipoprotein Cholesterol: A Meta-analysis.

* Kodama S,

* Tanaka S,

* Saito K,

* Shu M,

* Sone Y,

* Onitake F,

* Suzuki E,

* Shimano H,

* Yamamoto S,

* Kondo K,

* Ohashi Y,

* Yamada N,

* Sone H.

Department of Lifestyle Medicine and Nutritional Sciences,

Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo, Japan 112-8610.

sone.hirohito@....

BACKGROUND: Aerobic exercise is believed to reduce the risk of

cardiovascular disease partially through increasing serum levels of

high-density lipoprotein cholesterol (HDL-C). However, this effect

varies considerably among exercise intervention studies. METHODS:

Electronic database searches of MEDLINE (1966-2005) for randomized

controlled trials that examined the effect of exercise training on

HDL-C level. RESULTS: Twenty-five articles were included. Mean net

change in HDL-C level was statistically significant but modest (2.53

mg/dL [0.065 mmol/L]; P<.001). Minimal weekly exercise volume for

increasing HDL-C level was estimated to be 900 kcal of energy

expenditure per week or 120 minutes of exercise per week. Univariate

regression analysis indicated that every 10-minute prolongation of

exercise per session was associated with an approximately 1.4-mg/dL

(0.036-mmol/L) increase in HDL-C level. In contrast, there was no

significant association between exercise frequency or intensity.

Multiple meta-regression analyses demonstrated that subjects with a

body mass index (calculated as weight in kilograms divided by height

in meters squared) less than 28 and total cholesterol level of 220

mg/dL [5.7 mmol/L] or more experienced an approximately 2.1-mg/dL

(0.054-mmol/L) larger increase in HDL-C level than those with a body

mass index of 28 or more and total cholesterol level less than 220

mg/dL (5.7 mmol/L). CONCLUSIONS: Regular aerobic exercise modestly

increases HDL-C level. There appears to exist a minimum exercise

volume for a significant increase in HDL-C level. Exercise duration

per session was the most important element of an exercise

prescription. Exercise was more effective in subjects with initially

high total cholesterol levels or low body mass index.

PMID: 17533202