Peripheral Effects of Exercise on Cardiovascular Health (STRRIDE I)
Condition: Cardiovascular Diseases; Heart Diseases; Obesity; Hyperlipidemia; Insulin Resistance; Metabolic Syndrome X
MeSH terms: Cardiovascular Diseases; Heart Diseases; Metabolic Syndrome; Insulin Resistance; Hyperlipidemias
Study type: Interventional
Phase: Phase 2

Summary: 
      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.
    

Detailed description: 
      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.
    

Intervention name(s): physical activity
Intervention type(s): Behavioral
Allocation: Randomized
Primary purpose: Prevention