Effects of exercise on emerging and traditional cardiovascular risk factors.
BACKGROUND
Common cardiovascular disease risk factors (e.g., insulin and aerobic fitness) are improved with exercise; however, few studies have addressed the potential for training to modify emerging cardiovascular disease risk factors such as homocysteine and high-sensitivity C-reactive protein.


METHODS
Sedentary adults (n = 324, 48.9 +/- 8.4 years) were randomized to four groups differing in training intensity (moderate = 45-55% or high = 65-75% of heart rate reserve) and frequency (low = 3-4, 30-min sessions/week or high = 5-7, 30 min-sessions/week).


RESULTS
Within-group changes in homocysteine, insulin, and aerobic fitness were significant (all P < 0.0125). Furthermore, homocysteine increased in the high-intensity-low-frequency (0.98 +/- 2.32 micromol/L) and high-intensity-high-frequency (0.93 +/- 2.56 micromol/L) groups, while aerobic fitness increased in the moderate-intensity-high-frequency (0.99 +/- 2.01 mL min(-1) kg(-1)) and high-intensity-high-frequency (1.77 +/- 2.97 mL min(-1) kg(-1)) groups (all P < 0.003). The change in aerobic fitness was greater in the high-intensity-high-frequency compared to the moderate-intensity-low-frequency group (1.77 +/- 2.97 vs. 0.36 +/- 2.10 mL min(-1) kg(-1), P = 0.0014) (effect size estimate = 0.60 mL min(-1) kg(-1)). The main effects for intensity, with respect to the change in insulin (effect size estimate = 0.46 microU/mL), and frequency, with respect to the change in aerobic fitness (effect size estimate = 0.38 mL min(-1) kg(-1)), were significant (P < 0.0125).


CONCLUSIONS
Although frequent bouts of higher intensity exercise were particularly effective in reducing fasting insulin and improving fitness, they resulted in slightly increased homocysteine levels.
Duncan
Glen E
GE
Department of Epidemiology, Nutritional Sciences Program, University of Washington, Seattle, WA 98195, USA. duncag@u.washington.edu
Perri
Michael G
MG
Anton
Stephen D
SD
Limacher
Marian C
MC
Martin
A Daniel
AD
Lowenthal
David T
DT
Arning
Erland
E
Bottiglieri
Teodoro
T
Stacpoole
Peter W
PW
D000328:Adult; D000886:Anthropometry; D002097:C-Reactive Protein / Q000032:analysis; D002318:Cardiovascular Diseases / Q000097:blood / Q000517:prevention & control*; D004032:Diet; D015444:Exercise; D005081:Exercise Therapy / Q000379:methods; D005260:Female; D006710:Homocysteine / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood; D008019:Life Style; D008297:Male; D010101:Oxygen Consumption; D010349:Patient Compliance; D010809:Physical Fitness; D012307:Risk Factors
D007328:Insulin; D006710:Homocysteine; D002097:C-Reactive Protein