Cardio fitness is a strong, consistent predictor of morbidity and mortality (bjsm.bmj.com)

Article summary

The article discusses the relationship between cardio fitness and health outcomes, with research suggesting that higher cardio fitness is associated with lower morbidity and mortality. However, the direction of causality is unclear, and it is possible that being sick can lead to lower cardio fitness rather than the other way around. The article's findings are based on observational data and do not necessarily imply that increasing cardio fitness will lead to better health outcomes. The relationship between cardio fitness and health is complex and influenced by various factors.

Main themes

• Cardio fitness and health
• Causality and correlation
• VO2 max and measurement
• Exercise and training
• Heart rate and health

What commenters say

• Some commenters argue that the relationship between cardio fitness and health is obvious, but research is necessary to confirm hypotheses and rule out alternative explanations.
• There is disagreement about the transferability of VO2 max across different exercises and activities, with some arguing that it is highly specific and others claiming that it can be transferred to some extent.
• The accuracy of VO2 max estimates from wearable devices such as the Apple Watch is questioned, with some commenters reporting inconsistent or unrealistic results.
• Some argue that cardio fitness is highly trainable, but others point out that individual responses to training can vary greatly and that achieving significant improvements can be challenging.
• The importance of technique and muscle recruitment in determining VO2 max is emphasized by some commenters, while others argue that heart and lung function are more critical factors.
• There is discussion about the limitations of using VO2 max as a metric for elite athletes, with some arguing that it is not a useful indicator of performance at high levels.