Abstract
The purpose of the present study was to examine the effect of circuit training (CT) on resting heart rate variability (HRV) and other cardiovascular disease (CVD) risk factors such as blood lipids and blood glucose and on fitness components. Twenty-four healthy untrained adults (age 26.5 ± 5.1 years; height 1.67 ± 8.4 m; weight 66.8 ± 15.1 kg; 26.3% ± 5.2%; maximum oxygen uptake (VO2max) 48.5 ± 10.0 ml.kg-1.min-1) were assigned to either CT (n = 12) involving bodyweight exercises, or control (CON, n = 12) groups. Prior to the start and following the end of the six-week training period, time-, frequency-domain and nonlinear measures of resting HRV, arterial blood pressure, body composition, fasting blood lipids, lipoproteins and glucose, VO2max, upper body muscular endurance (UBME) and abdominal and hip flexor (AHFME), back strength (BS) and handgrip were assessed. None of the resting HRV measures (P > 0.05) were affected by the CT intervention. However, diastolic blood pressure decreased (P = 0.03), lean body weight (P = 0.03) increased, VO2max (P = 0.03), UBME (P ＝ 0.001), AHFME (P = 0.04), and BS (P = 0.03) were significantly higher following CT, whereas the other variables were not influenced by the CT. Six-week of CT involving bodyweight exercises has no significant impact on resting HRV. However, this type of training might decrease the risk for development of CVD by reducing arterial blood pressure and by improving body composition, aerobic capacity, muscular endurance and strength.
Highlights
According to the World Health Organization (WHO), more people die annually from cardiovascular diseases (CVD) than from any other cause [1]
heart rate variability (HRV) was analyzed by the use of linear methods but these means resulted in loss of information on the dynamic patterns used by cardiovascular regulation systems to adjust heart rate (HR) and blood pressure [6]
The current results indicate that circuit training (CT) may increase upper body muscular endurance (UBME) and AHFME confirming the particular tested hypotheses
Summary
According to the World Health Organization (WHO), more people die annually from cardiovascular diseases (CVD) than from any other cause [1]. An estimated 17.3 million people died from CVD in 2008, representing 30% of all global deaths. Of these 17.3 million deaths, an estimated 7.3 million were due to coronary heart disease and 6.2 million were due to stroke. Increased HRV is linked to improved prognosis and lower CVD mortality [7]. This suggests that HRV could be a valuable tool in predicting future cardiac events, and that any type of exercise intervention that is proven to improve HRV might reduce the risk of such events
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