1.d. Fitness 

Rationale: Seven RCTs testing the effects of weight loss on blood pressure in overweight and obese individuals also had measures of cardiorespiratory fitness, as measured by maximal oxygen uptake (346, 363, 369, 375, 377, 380); or submaximal heart rate tests (365). Weight loss was accompanied by increased fitness, primarily if the intervention included increased physical activity or physical activity combined with diet (346, 363, 375, 377, 380). These studies were not designed to test whether increased cardiorespiratory fitness reduces blood pressure independently of weight loss in overweight and obese adults. By contrast, in 3 meta-analyses of 68 controlled studies of physical activity conducted in normotensive and hypertensive individuals, obesity was not an outcome measure nor was it included in the eligibility criteria. These meta-analyses showed that aerobic exercise to increase cardiopulmonary fitness significantly reduces blood pressure independent of or in the absence of weight loss (396-398).