In order to differentiate the research from that on tapering - where people reduce their load before big competitions - the studies focused on subjects who reduced their training for at least four weeks. The focus was also on athletic performance and not weight loss or health, which is an important distinction to note.
The review found that as far as endurance goes, you can get away with as little as two sessions a week as long as you maintain volume and intensity of your workouts. That said, maintaining VO2 max isn’t the same as maintaining your ability to perform long-duration endurance activities. And so they caution that you shouldn’t expect to run your best marathon after months of just two-a-week sessions. But when it comes to intensity, it appears training does matter. Dropping training intensity leads to declines in VO2 max and long endurance. It suggests that although you might be able to get away with training less often or for shorter durations, you can’t get away with training easy.
Studies on maintaining strength were similar, and showed that you can reduce both the frequency and volume of workouts as long as you maintain the intensity, allowing you to preserve both maximum strength and muscle size for several months. Researchers found that even just training once a week is enough to maintain strength and muscle size, but again this is simply about maintaining existing strength, not gaining strength. Still, for anyone that’s been thrown into a fit of anxiety when sickness or work forces you to decrease your training for a week or two, this should help you get some sleep at night.
