There comes a point in almost every fitness lover’s life when they consider throwing in the towel after
a workout—both figuratively and literally. Blame it on your looming work
deadlines, or the stubborn needle on the scale, or even just plain old boredom.
That’s normal. But here’s why you shouldn’t follow through on the temptation to
just quit: There are plenty of benefits to exercise, but they’re not permanent.
In fact, many of those hard-earned gains will start to disappear in as little
as two weeks, says Farah Hameed, MD, a sports medicine physician with
Here’s exactly what you can expect to happen to your body if you give up
In the study, when a group of long-term endurance runners took a 10-day
exercise hiatus, their subsequent MRIs showed a reduction in blood flow to the hippocampus, the part
of the brain that’s associated with memory and emotion. The researchers point
out that although the runners didn’t experience any cognitive changes over the
period, more long-term studies are needed.
Within two weeks: Your endurance will plummet and your vitals may spike
After just 14 days, you might have a harder time climbing a flight of stairs or
keeping up with your colleagues during the monthly kickball game. The reason
you’re so winded? Skipping sweat sessions causes a drop in your VO2 max, or the maximum
amount of oxygen your body can use. It can dip by about 10% after two weeks,
says Dr. Hameed. It only gets worse from there: After four weeks, your VO2 max
can drop by about 15%, and after three months, it can fall about 20%—“and those
are conservative estimates,” Dr. Hameed notes.
Staying even slightly active can help: One 2009 study found that male kayakers
who took a five-week break from their training saw an 11.3% drop on average in their VO2 max, while those who worked in a handful of exercise sessions
during each week only saw a 5.6% drop.
Even if you don’t notice a change in your speed or strength, you might
experience a sharp rise in your blood pressure and blood glucose
levels—something that could be more serious for people with diabetes or high
blood pressure, says Dr. Hameed.
Researchers from South Africa found that a two-week exercise break was enough to
offset the blood pressure benefits of two weeks of high-intensity interval
training; another 2015 study in the Journal of Applied Physiology found that people who did an eight-month bout of
resistance and aerobic exercise saw an improvement in the blood glucose levels,
but lost almost half of these benefits after 14 days of inactivity.
Within four weeks: Your strength will start slipping
Dr. Hameed estimates that some people will notice their strength declining
after about two weeks of inactivity, while others will begin to see a
difference after about four weeks. The silver lining: Our strength probably
diminishes at a slower rate than our endurance, and one 2011 study in the Journal of Strength and Conditioning found that when one group of men stopped doing
resistance training, they still had some of their strength gains up to 24 weeks
Within eight weeks: You might gain fat
Dr. Hameed estimates that people will start to notice a physical change—either
by looking in the mirror, or at the number on the scale—after about six weeks.
Even elite athletes aren’t immune to the rebound.
A 2012 study in the Journal of Strength and Conditioning Research found that competitive swimmers who took a five-week
break from their training experienced a 12% increase in their levels of body
fat, and saw a boost in their body weight and waist circumference. (We should
also point out that these athletes weren’t totally sedentary—they still did some
light and moderate exercise.) And a 2016 study found that elite Taekwondo
athletes who took an eight-week hiatus from exercise experienced an increase in
their levels of body fat and
a decrease in muscle mass, too.