How long does it take to get fit?

I just noticed an interesting study from the May issue of Medicine & Science in Sports & Exercise. German researchers had 18 untrained subjects go on a one-year, three-days-a-week walking and jogging program, and measured their progress during the year see how their fitness progressed. The key was that they controlled the intensity of the 45-minute sessions using heart rate, so that the subjects were “trying” at roughly the same level throughout the year.

So how long does it take to see real gains, and when do they start to plateau? Well, it depends on what indicators you look at, but the researchers basically conclude that after six months, you need to start trying harder or else your progress will stagnate:

Beginners in recreational endurance exercise are advised to increase their training stimulus after 6 months of training to maintain training effectiveness because no further significant changes in endurance capacity were observed thereafter.

The benefits actually show up very quickly in parameters like heart rate, maximal oxygen uptake and running velocity — and oxygen uptake, in particular, was still increasing steadily at the end of the year-long study.

The point here is that you have to keep raising the bar for yourself. As you get fitter, you’re going to be able to go faster and farther with the same effort — but that’s not enough. You actually have to put out more effort to keep the gains coming — increasing your effort, or how long you’re out there, or how often you do it.