It takes work to stay in shape which is part of why working out on the regular is so important. But sometimes, for whatever reason, you miss a workout. And sometimes missing that workout can lead to missing several workouts....
To properly understand what happens when we stop working out, we should first take a look at what happens when we DO exercise. Exercises that are on the endurance end of the scale -- like running or rowing -- all have a profound impact on measures of fitness such as oxygen uptake in the body.
Andreas Bergdahl, an assistant professor in cardiovascular physiology at Montreal’s Concordia University, says that regular exercise has 4 major consequences in the body:
- Increased ability of the heart to eject blood
- Increased ability of the blood vessels to send blood to where blood is needed
- Increased number of capillaries (the vessels that deliver oxygen and ‘food’ to the muscles)
- increased size and the number of mitochondria (the “power plants” of the cells).
These changes all lead to a more efficient use of oxygen and nutrients. “Instead of sending lots of blood to your gut, kidneys and skin, all with limited ability to enhance someone’s performance, your body has trained its capacity to use the resources for maximizing performance,” says Bergdahl.
Harry Pino, a senior exercise physiologist at the Sports Performance Center at NYU Langone Medical Center backs up this information when he says that regular exercise increases muscle strength, power, coordination, stability, and flexibility and do so while improving endocrine measures, such as sugar and fat levels.
So, you've got your body running like a machine, but then you take a break. Maybe you're injured, or maybe it is something else entirely. No matter the reason, you've stopped. What happens to your body? It isn't good. The negative impact is, I'm sorry to say, directly linked to your level of fitness in the first place. The more fit you are, the worse it will be.
The VO2 Max (your oxygen uptake measurement) is usually the first to decline. After that comes declines in muscle structure, power, strength, stamina, and coordination. When you are in "detraining," as this is often called, you can also expect a rise in sugar levels and blood pressure. “There are studies indicating a decline of 7 to 10% of VO2 after 12 days of sudden inactivity, 14 to 15% after 50 days, and 16 to 18% after 80 days,” says Bergdahl. “Maximal values for cardiac output, stroke volume [the amount of blood pumped out of the heart during each contraction] and ability of mitochondria to extract oxygen each decline along the same lines while the heart rate increases.” Well, that doesn't sound good.
“It’s shocking to see what happens to the body,” says Pino. “We start to see lots of changes to muscle, strength, and fat levels—it really deteriorates your structural well-being.”
Cardio is the first thing to go but muscle mass isn't far behind. How quickly we lose muscle mass depends on age. The older we are, the more quickly we lose muscle.
Pino says that aerobic endurance drops within three weeks of detraining in highly trained athletes but that even after twelve weeks they retain a large amount of bulk strength and endurance. Even if you are not an elite athlete and just someone who regularly exercises, within 10-28 days you will notice diminished muscle strength and a loss in power, including speed and agility, mobility, moving from side-to-side, the ability to stop on a dime, and a loss of coordination.
And don't forget about that myth about muscle turning into fat: “What really happens is that the muscle cells —which are completely different than fat cells—become smaller, because now you don’t have a demand of power and strength—they’re not growing,” Pino said. “That’s atrophy. Then you have fat cells that are starting to get larger and bigger, which will lead to changes in your appearance. Instead of looking lean and trim, you start feeling bloated and round.”
Being inactive can lead to a whole whack of health problems but it can also hasten aging. The functional capacity of our bodies declines with age but exercise works to slow it down. You can't avoid it, but you can slow it up a little.
“Physiologic and performance measures improve rapidly during childhood and achieve a maximum between late adolescence and approximately age 30,” says Bergdahl. “The decline starts shortly after—sometimes after 40 depending on the body system—and the changes are similar to detraining.”
Regular exercise, says Bergdahl, will slow down this deterioration and will keep your body “younger” for a longer period of time.
Science has just told you what you already know deep inside: a sedentary lifestyle is bad! So even if you've just fallen off the fitness wagon, it is important to get back on. Don't be discouraged by your losses -- a little more hard work and you'll be back where you were.
No matter your reasons for skipping a workout, try to stay at least a little active.
Do something, it is better than nothing!