Background: Heart rate recovery (HRR) is an independent risk factor for cardiovascular disease (CVD) and mortality, but whether it is modifiable and can improve with weight loss is unclear. We sought to determine the effects of weight loss on HRR and its association with traditional CVD risk markers.
Methods: Heart rate recovery (defined as the decrease in heart rate from peak heart rate to that measured 1 minute after a standardized graded treadmill test) and a range of established cardiovascular risk factors were measured in 42 overweight and obese men (body mass index 33.8 +/- 0.6 kg/m2, mean age 46.5 +/- 1.3 years) who had no symptoms of CVD but had components of the metabolic syndrome before and after 12 weeks of weight loss.
Results: There was a 9% weight reduction (P < .001), with losses of 6.3 +/- 0.6 kg of fat mass (P < .001) and 3.1 +/- 0.6 kg of non-bone fat-free mass (P < .001). There were significant reductions in waist circumference, blood pressure, plasma triglycerides, total cholesterol, low-density lipoprotein cholesterol, triglyceride/high-density lipoprotein ratio, C-reactive protein, plasma insulin, glucose, and insulin resistance (P < .05). Although peak heart rate remained unchanged, HRR at 1 minute improved from 33.1 +/- 1.4 to 36.9 +/- 1.3 beats/min (P < .001) after weight loss. There was no change in cardiorespiratory fitness (P = .30); neither was there any change in physical activity levels (P = .67). The improvement in HRR was significantly correlated with decreases in body weight, body mass index, waist circumference, plasma glucose, serum triglycerides, and triglyceride/high-density lipoprotein ratio; however, it was only independently associated with changes in weight and plasma glucose concentrations.
Conclusion: In addition to improving a range of well-accepted cardiovascular and metabolic risk factors, weight loss also improves HRR after exercise, a less recognized risk factor.