What is the recommended frequency for cardiorespiratory exercise?

Cardiorespiratory Fitness

Although cardiorespiratory fitness [CRF] is determined by a number of nonmodifiable factors, such as gender, age, and genetic factors, it has also been considered in recent years an objective indicator of physical activity and used to assess the relationship between physical activity and health status [30,31]. Therefore, relationships observed between indicators of abdominal obesity and CRF may indirectly prove a relationship between physical activity and abdominal obesity. Of particular importance are the results of studies that made direct measurements of VAT. The earliest study on the subject reported CRF to show a significant correlation only with the amount of total abdominal adipose tissue and SAT, but not with VAT [32]. In another study, however, CRF was observed to negatively correlate with VAT in 13-year-old girls [r = −0.45] and boys [r = −0.43] [33]. Similar results were obtained in a study of white and black young people aged 8–17 years [r = −0.43 and r = −0.68, respectively] [34].

In 8-year-olds within the same BMI category, children with high CRF [assessed using a maximal multistage 20-m shuttle run test], had a significantly lower WC [P = 0.001] and a lower fat percentage in the abdominal region, as measured by DEXA [P