Peripheral Effects of Exercise on Cardiovascular Health (STRRIDE I)
Peripheral Effects of Exercise on Cardiovascular Health (STRRIDE I)
To investigate the separate effects of the amount of exercise and exercise intensity on
 cardiovascular risk factors in overweight men and women with mild to moderate dyslipidemia.
BACKGROUND:

 Substantial evidence supports a favorable relationships between cardiovascular fitness,
 physical activity and cardiovascular health. In particular, it is well established that
 increased levels of physical activity result in favorable improvements in lipid and
 carbohydrate metabolism. There is also evidence that increased physical activity and
 cardiovascular fitness have beneficial effects on cardiovascular health independent of the
 effects on specific cardiovascular risk factors. One hypothesis proposes that the beneficial
 effects of regular exercise in humans is mediated through peripheral mechanisms, in
 particular through the chronic adaptations in skeletal muscle to habitual exercise. The
 exercise exposures required to achieve health benefits in humans are poorly defined and the
 mechanisms through which these beneficial adaptations occur are poorly understood. The study
 will investigate the peripheral biological mechanisms through which chronic physical activity
 alters carbohydrate metabolism and lipid metabolism, resulting in improvements in these
 parameters of cardiovascular health and fitness in humans.

 DESIGN NARRATIVE:

 In this clinical trial, Studies of a Targeted Risk Reduction Intervention through Defined
 Exercise (STRRIDE I), subjects were randomly assigned to one of three graded exercise
 training regimens or a sedentary control group and asked to train, after an initial ramp
 period of up to two months, for six months at a given exercise intensity and dose. Parameters
 reflecting changes in carbohydrate and lipid metabolism were studied at an integrative
 physiologic level and with measurable biological endpoints in peripheral skeletal muscle
 (e.g., capillary surface area). It was proposed that the elucidation of the peripheral
 mechanisms mediating the favorable responses in carbohydrate and lipid metabolism to chronic
 physical activity would lead to better understanding of the health benefits conferred by
 physical activity and cardiovascular fitness in humans and point the way toward better
 exercise recommendations for clients with significant cardiovascular risk factors. The
 purpose of this study was to investigate the peripheral biological mechanisms through which
 chronic physical activity altered carbohydrate metabolism and lipid metabolism, resulting in
 improvements in these parameters of cardiovascular health and fitness in humans. The driving
 hypothesis was that health benefits derived from habitual exercise were primarily mediated
 through adaptations occurring in skeletal muscle, probably related to alterations in exposed
 capillary surface area in skeletal muscle induced by exercise training. The investigators
 used graded exercise regimens in moderately obese human subjects with mild to moderate lipid
 metabolic abnormalities to investigate whether induced alterations in skeletal muscle fiber
 type, metabolic capacity and capillary surface area accounted for favorable alterations in
 insulin sensitivity and glucose metabolism, lipoprotein levels and lipid metabolism.
Inclusion criteria: age 40 to 65 years, sedentary (exercise less than two times per week),
 overweight or mildly obese (BMI 25 to 35 kg/m2) with mild to moderate lipid abnormalities
 (either LDL cholesterol 130 to 190 mg/dl; or HDL cholesterol < 40 mg/dl for men, or 5 < 45
 mg/dl for women). Women were postmenopausal.

 Exclusion criteria: diabetes; hypertension; other metabolic or musculoskeletal diseases;
 current use of or intent to diet; use of confounding medications; overt presence of
 coronary heart disease; or unwillingness to be randomized to any group.