VO2 max

I quit smoking just to stop coughing in the morning: three weeks later, my running watch showed a number I couldn’t explain

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I quit smoking just to stop coughing in the morning: three weeks later, my running watch showed a number I couldn't explain

Quit smoking and your running watch suddenly shows you’re fitter than ever? That’s not a sensor glitch—it’s real physiology happening fast. Within three weeks, your heart stops working overtime, oxygen delivery normalizes, and your VO2 max estimate climbs noticeably, even before your training changes.

I skipped all my workouts during a two-week summer holiday: when I saw my VO2 max on my return, I understood what my body had lost first

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I skipped all my workouts during a two-week summer holiday: when I saw my VO2 max on my return, I understood what my body ...

Just two weeks away from exercise is enough to trigger a measurable decline in VO2 max—your body’s aerobic capacity—before you lose any meaningful strength. Research shows plasma volume and mitochondrial function are the culprits, but the good news is recovery happens faster than you’d expect.