According to running guru Hal Higdon, “Research by Edward F. Coyle, Ph.D. at the University of Texas at Austin suggests that runners begin to detrain (lose their fitness) after 48 to 72 hours, and that it takes two days of retraining to regain the fitness lost for every single day of training skipped” (para. 4). Well-trained athletes tend to lose the most fitness the quickest, as compared to less-trained individuals. Dr. Coyle describes a study done by David L. Costill at Ball State University on swimmers, finding that oxidative capacity and fitness declined by 50% after no training for 12 days. He writes, “There are some adaptations you keep for at least 3 months, namely the cardiovascular adaptations of heart size and muscle capillary density” (Higdon, para. 10). Higdon suggests that during periods of recovery after an endurance training cycle to include 1 to 3 days of maintenance training each week. An assistant professor of cardiovascular physiology at Concordia University in Montreal, Andreas Bergdahl agrees “… that what applies to an elite athlete after one week might take a sedentary individual one or two months to experience” (Dvorsky, 2015). First VO2 max declines, followed by changes in muscle structure and declines in power, strength, stamina, and coordination. A rise in blood sugar and blood pressure may also be seen. A fit individual essentially becomes sedentary with detraining over time (Dvorsky, 2015).
Losses in muscle mass occur after cardio is affected. The rate of muscle degradation is proportionate with age, which explains why regular weight training slows muscle atrophy in the elderly but does not stop it altogether. In both detraining and the aging process, slow twitch muscle fibers (think endurance) decrease quickly at first, then at a slower rate, starting within the first two weeks. Then the oxidative capacity of the fast twitch muscle fibers (think explosive movements) declines, decreasing their ability to produce energy (Dvorsky, 2015). Harry Pino, a senior exercise physiologist at the Sports Performance Center at NYU Langone Medical Center, adds that regardless if an individual is an elite athlete or someone who works out on a regular basis, between 10 and 28 days of detraining, there is often a noticeable decrease in muscle strength and power, “… including speed and agility, mobility, moving from side-to-side, the ability to stop on a dime, and a loss of coordination” (Dvorsky, 2015). He describes that muscle cells become smaller as fat cells start to get larger, changing the person’s appearance. That explains why a person might go from feeling lean and trim to feeling bloated and out of shape (Dvorsky, 2015).
The time it takes to regain fitness depends on the duration of inactivity and the former fitness level. The good news is that the individual often starts out at a higher level than when they first started that particular exercise due to muscle memory (Loews, 2016). The best strategy, rather than cutting out physical activity altogether, is to maintain some level of exercise as a form of active recovery phase. In a study conducted in 2005, sedentary men strength-trained 3 times per week for 3 months, then reduced to once per week. Results showed that the men kept almost the same level of strength that was developed during the first 3 months of the study. Technically speaking, one would need to train at 70% of their VO2 max at least once per week to maintain fitness, depending on the level of baseline fitness (Quinn, 2020).
One could have the best of intentions about hitting the gym and love every second of working out, but the truth is, life happens. Unfortunately, as the saying goes, ‘if you don’t use it, you lose it’, and this can also describe what happens during prolonged periods of inactivity. It may seem daunting at first, but the best way to get back into it is to just do it! Remember your why, and enjoy the journey!
Hugs,
The UFit Team
