Aerobic Exercise and Strength Training Effects on Cardiovascular Sympathetic Function in Healthy Adults

Abstract

Objective Exercise has widely documented cardioprotective effects, but the mechanisms underlying these effects are not entirely known. Previously, we demonstrated that aerobic but not strength training lowered resting heart rate and increased cardiac vagal regulation, changes that were reversed by sedentary deconditioning. Here, we focus on the sympathetic nervous system and test whether aerobic training lowers levels of cardiovascular sympathetic activity in rest and that deconditioning would reverse this effect. Methods We conducted a randomized controlled trial contrasting the effects of aerobic (A) versus strength (S) training on indices of cardiac (preejection period, or PEP) and vascular (low-frequency blood pressure variability, or LF BPV) sympathetic regulation in 149 young, healthy, and sedentary adults. Participants were studied before and after conditioning, as well as after 4 weeks of sedentary deconditioning. Results As previously reported, aerobic capacity increased in response to conditioning and decreased after deconditioning in the aerobic, but not the strength, training group. Contrary to prediction, there was no differential effect of training on either PEP (A: mean [SD] −0.83 [7.8] milliseconds versus S: 1.47 [6.69] milliseconds) or LF BPV (A: mean [SD] −0.09 [0.93] ln mm Hg2 versus S: 0.06 [0.79] ln mm Hg 2) (both p values > .05). Conclusions These findings, from a large randomized controlled trial using an intent-to-treat design, show that moderate aerobic exercise training has no effect on resting state cardiovascular indices of PEP and LF BPV. These results indicate that in healthy, young adults, the cardioprotective effects of exercise training are unlikely to be mediated by changes in resting sympathetic activity. Trial Registration Clinicaltrials.gov identifier: NCT00358137.

No Effect of Exercise on Urinary 6-Sulfatoxymelatonin and Catecholamines in Young Women Participating in a 16-Week Randomized Controlled Trial

“…Even though short-term physical exercise acutely increases plasma melatonin levels in healthy humans (2, 3), we found that 150 minutes per week of exercise for four months did not affect melatonin levels. Recently, it has been shown that 12 weeks of exercise at 70% does not alter sympathetic nervous system (SNS) activity in healthy people (6). This could be an explanation why we did not see any effects of exercise on melatonin levels given that catecholamine secretion, which is directly related to the biosynthesis of melatonin by the pineal gland, is triggered by SNS activity.…”

Visit-to-Visit Variability and Reduction in Blood Pressure After a 3-Month Cardiac Rehabilitation Program in Patients With Cardiovascular Disease

“…24,25) Aerobic exercise has been associated with the suppression of sympathetic nerve activity in humans. 26,27) In addition, exercise training improved the gain and reduced the time delay of arterial baroreflex control of muscle sympathetic nerve activity in HF patients. 28) Arterial stiffness significantly decreased over a 20-week CR program in patients with established IHD.…”

“…This effect may be due to the suppression of sympathetic nerve activity. 26,27) Based on 36 years of follow-up data from the Framingham Study, heart rate may be an independent risk factor for cardiovascular death in patients with HTN. 34) An increase of 5 bpm in the morning HR measurement was associated with a 17% increase in the risk of cardiovascular mortality.…”

Improving the Hamstrings-to-Quadriceps Strength Ratio in Sedentary Women: Comparison of Stabilization Training and Aerobic Training After a 6-Months Follow-up

“…Cardio-protective effects, metabolic benefits, and improvements on muscle strength had been areas of interest (4)(5)(6). However, Pilates-based spinal stabilization training has been more and more popular lately, especially among women, and has become a beneficial adjunctive treatment to improve flexibility, enhance control-mobility of the trunk and pelvic segments, and to enhance functional capacity even in patients with heart failure (7)(8)(9).…”