Linear and non-linear analysis of heart rate variability in master athletes and healthy middle-aged non-athletes.

The present study examined the autonomic cardiac modulation of veteran athletes by the use of traditional and modern methods of heart rate variability (HRV) analysis. Twenty-nine healthy male master soccer players were divided into two groups; group A consisted of fourteen participants (age 48.9±5.8 years), who were engaged to regular aerobic exercise and group B of fifteen sedentary ones (age 50.8±5.7 years). Sixteen age-matched non-athletes formed control group C. All participants underwent ambulatory 24-h continuous electrocardiogram monitoring for the calculation of time and frequency domain HRV indices. Additionally, Poincaré analysis SD1 and SD2 as well as multiresolution wavelet analysis σwav(16) and σwav(32) markers were calculated. Time-domain indices were significantly increased in group A compared to groups B and C. Group A presented greater values of SD1 (by 43%, p<0.01 and 34.4%, p<0.05 than groups B and C respectively) and SD2 (by 26% compared to B and by 34.1% to C, p<0.05). Index σwav(16) was higher in group A than in B and C by 35.6% (p<0.01) and 23.5% (p<0.05) respectively and so did σwav(32) by 22% (p<0.05) and 24% (p<0.05). Strong correlations were reported among indices. In conclusion, physically active master athletes attain better cardiac autonomic activity than sedentary counterparts, as proved by the application of Poincaré and multiresolution wavelet analyses, which can be useful research tools of cardiac autonomic modulation in sports cardiology.