Long-term athletic training does not alter age-associated reductions of left-ventricular mid-diastolic lengthening or expansion at rest

The Influence of Age and Exercise Training Status on Left Ventricular Systolic Twist Mechanics in Healthy Males-An Exploratory Study

Age-related differences in twist may be mitigated with exercise training, although this remains inconclusive. Moreover, temporal left ventricular (LV) systolic twist mechanics, including early-systolic (twistearly), and beyond peak twist (twistpeak) alone, have not been considered. Therefore, further insights are required to ascertain the influence of age and training status on twist mechanics across systole. Forty males were included and allocated into 1 of 4 groups based on age and training status: young recreationally active (YRA, n = 9; 28 ± 5 years), old recreationally active (ORA, n = 10; 68 ± 6 years), young trained (YT, n = 10; 27 ± 6 years), and old trained (OT, n = 11, 64 ± 4 years) groups. Two-dimensional speckle-tracking echocardiography was performed to determine LV twist mechanics, including twistearly, twistpeak, and total twist (twisttotal), by considering the nadir on the twist time-curve during early systole. Twisttotal was calculated by subtracting twistearly from their peak values. LV twistpeak was higher in older than younger men (p = 0.036), while twistpeak was lower in the trained than recreationally-active (p = 0.004). Twistpeak is underestimated compared with twisttotal (p < 0.001), and when early-systolic mechanics were considered, to calculate twisttotal, the age effect (p = 0.186) was dampened. LV twist was higher in older than younger age, with lower twist in exercise-trained than recreationally-active males. Twistpeak is underestimated when twistearly is not considered, with novel observations demonstrating that the age effect was dampened when considering twistearly. These findings elucidated a smaller age effect when early phases of systole are considered, while lower LV systolic mechanics were observed in older aged trained than recreationally-active males.

Six weeks of high intensity interval training (HIIT) facilitates a four year preservation of aerobic capacity in sedentary older males: A reunion study

Long-term implications of acutely increased cardiorespiratory fitness following short-term exercise interventions in older adults are unknown. In this study, we examined peak oxygen uptake (VO_2peak) after 4-years of 'free-living' after a high intensity interval training (HIIT) intervention. Seventeen lifelong exercisers (LEX) and 17 previously sedentary (SED) males (55-74 years of age in 2012) were tested four years (phase D) after our previous experiment which included 6-weeks of aerobic moderate intensity exercise (phase B), followed by 6-weeks of HIIT (phase C). At all stages, a standard incremental exercise protocol on a cycle ergometer was completed to determine VO_2peak. SED (P = 1.000, Cohen's d = 0.01) and LEX (P = 1.000, Cohen's d = 0.11) VO_2peak at phase D was not different from phase A (enrolment). SED experienced a large decrease in VO_2peak from phase C to phase D (32 ± 6 ml·kg·min^-1 to 27 ± 6 ml·kg·min^-1 [P < 0.001, Cohen's d = 0.81]). LEX experienced a small decrease in VO_2peak from phase C to phase D (42 ± 7 ml·kg·min^-1 to 39 ± 9 ml·kg·min^-1 [P < 0.001, Cohen's d = 0.46]). At phase D, LEX had greater VO_2peak than SED (P < 0.001, Cohen's d = 1.73). The proportion of subjects who reported discontinuing training, maintaining moderate training, and maintaining HIIT differed between groups (P = 0.023), with LEX self-reporting more HIIT, and SED self-reporting more discontinuation from exercise. Those who continued exercising experienced a reduction in VO_2peak over the four years from 39 ± 7 ml·kg·min^-1 to 36 ± 9 ml·kg·min^-1 (N = 25, P < 0.001, Cohen's d = 0.37), and those who discontinued exercising also experienced a reduction in VO_2peak from 30 ± 7 ml·kg·min^-1 to 25 ± 9 ml·kg·min^-1 (N = 9, P = 0.003, Cohen's d = 0.62). Four years after completing a brief period of aerobic exercise and HIIT, older males demonstrated a preservation of VO_2peak, irrespective of training status (LEX or SED). However, LEX exhibited greater VO_2peak than SED after 4-years of unsupervised 'free-living'. Notably, participants who discontinued exercising experienced a greater reduction in VO_2peak. These data suggest that a 6 weeks of supervised HIIT can facilitate the long term.