Cardiac dimensions, physical activity, and submaximal working capacity in youth of the Québec Family Study

Abstract

The relationships between cardiac dimensions and physical activity and submaximal working capacity were examined in 198 boys and 154 girls, aged 9-18 years, who were participants in the first phase of the Québec Family Study. The sample was divided into three age groups, 9-12 years, 13-15 years, and 16-18 years. Indicators of physical activity included estimated daily energy expenditure (EE) and time spent in moderate-to-vigorous physical activity (median metabolic equivalents of energy expenditure above resting metabolic rate >/=4.8). Submaximal physical working capacity (PWC(150)) was determined using a submaximal exercise test on a Monark cycle ergometer. Echocardiographically determined dimensions included posterior wall thickness, septal wall thickness, and left ventricular mass (LVM). The analyses were based on partial correlation and analysis of covariance, controlling for age and body surface area. Relationships between EE/physical activity variables and cardiac dimensions were low and, at best, moderate (r < 0.45). With subjects grouped into tertiles by indicators of physical activity, LVM was significantly different only among 16- to 18-year-old girls (157 g vs 134 g in the highest and lowest quartiles, respectively; P < 0.05). Correlations between cardiac dimensions and PWC(150) were also low (r < 0.30), with few significant relationships. In general, cardiac dimensions were not related to habitual physical activity and PWC(150) in young subjects aged 9-18 years. However, significant correlations were positive, as expected. LVM may be related to submaximal power output in boys since it accounts for 3% of the variance, after adjusting for age and BSA.

Interoceptive sensitivity and physical effort: Implications for the self‐control of physical load in everyday life

“…Fitness level was examined using a bicycle ergometer (“Ergo‐fit 300”) according to the PWC 150 protocol (e.g., Eisenmann et al, 2000; Haber et al, 1978; Katzmarzyk et al, 2000), which measures physical working capacity (PWC) at a heart rate of 150 beats per minute. For the calculation of the PWC 150 participants were required to cycle for 120 s with workloads varying from 0 to a maximum of 250 W. Initial workload was set at 0 W and increased in steps of 25 W. Heart rate was recorded during each trial of 120 s. Participants stopped cycling when their heart rate reached 150 beats per minute and the corresponding workload was registered as the PWC 150 and expressed per kilogram body weight (W·kg −1 ) (e.g., Eisenmann et al, 2000; Haber et al, 1978). Given, for example, a heart rate ≥150 bpm in the 175 W workload step, the PWC 150 workload was equal to 175 W.…”

Objectively measured daily physical activity related to cardiac size in young children

“…No relationship was found (r 5 0.00 in boys and À 0.09 in girls, both NS) between left ventricular mass indexed for BSA (LVMI) and questionnaire-assessed physical activity in 124 children aged 8-12 years participating in the Muscatine Study (Janz et al, 1996). Eisenmann et al (2000) found that questionnaire-estimated energy expenditure related to echocardiographic LVMI in 74 boys aged 9-12 years (r 5 0.24, Po0.05), whereas no such relation was found for MVPA. No relation was found between LVMI and questionnaire-estimated energy expenditure or MVPA in 53 girls.…”

“…No relation was found between LVMI and questionnaire‐estimated energy expenditure or MVPA in 53 girls. Neither study reported data on LVDDI or LAI (Janz et al, 1996; Eisenmann et al, 2000).…”

“…Furthermore, the results of various types of short-term endurance training programs have also been divergent, with some showing no change in cardiac size (Ricci et al, 1982), whereas others have reported alterations in cardiac size (Geenan et al, 1982;Obert et al, 2001Obert et al, , 2003. The hypothesis that an increased amount of daily physical activity may result in alterations of cardiac dimensions has also been evaluated in young subjects from the general population (Janz et al, 1996;Eisenmann et al, 2000), with divergent findings. Previous investigations (Janz et al, 1996;Eisenmann et al, 2000) have, however, used self-report methods to assess daily physical activity.…”

“…The hypothesis that an increased amount of daily physical activity may result in alterations of cardiac dimensions has also been evaluated in young subjects from the general population (Janz et al, 1996;Eisenmann et al, 2000), with divergent findings. Previous investigations (Janz et al, 1996;Eisenmann et al, 2000) have, however, used self-report methods to assess daily physical activity. Self-report methods are known to have limited accuracy in the measurement of daily physical activity in subjects of all ages and are considered inappropriate to use in children under the age of 10-12 years (Harro & Riddoch, 2000;Kohl et al, 2000;Sallis & Saelens, 2000).…”