Cardiorespiratory fitness may be the most modifiable predictor of how long you live.
How cardiorespiratory fitness predicts long-term mortality, what the research shows, and why small, sustained improvements compound over decades.
Training through winter supports your immune system. Here's the research.
The "immune open window" theory got the post-exercise dip wrong. A 2018 review of the evidence explains why training through winter supports your immune system rather than running it down.