Use It or Lose It. But How Fast?

What Happens When We Stop Exercising and How Soon?

The most “exercise” I got last week. (No regrets!)

I have a confession.
The last time I did official exercise was 10 days ago.

This is pretty unusual for me.
Steve and I spent the week in New York with Luke and Jess helping out with our grandchildren, including a very busy 2½-year-old, and a brand-new 3-week-old baby. We cooked, cleaned, danced, and played. In the off-baby hours, we just laid low and visited.

Granted, we were active, not sedentary. We ate less sugar (Elo can’t have much), snacked less and ate lots earlier than usual. So in some ways, it a pretty darn healthy week! 

While I need and miss my mental Mojo fix, Steve and I wondered Steve and I wondered: How quickly do we actually lose fitness when we stop exercising? 

If you’ve been off your schedule, injured or unmotivated this summer – I think you will find this research by the BBC both reassuring and motivating.

So…how long does “use it or lose it” actually take?

So, what actually happens when we stop challenging exercise?

To become strong and fit, we have to ask our bodies to do more than they’re accustomed to doing. Exercise scientists call this exceeding our “habitual load.”

Our heart pumps harder. Our muscles produce more force. Our cardiovascular system has to deliver more oxygen. Our body gets the message: Apparently we’re going to keep doing this. Time to upgrade the equipment!

Our bodies adapt to what we ask them to do.

When we remove that demand for long enough, our bodies adapt again. The extra capacity we built is expensive to maintain, and our very efficient bodies aren’t particularly interested in maintaining equipment we’re no longer using.

So how fast does the “use it or lose it” part actually happen?

After 48 hours:

Technically something is happening, but you won’t notice.

Within just 48 hours of stopping exercise, our plasma volume, the liquid part of our blood, begins to decrease.

Why does that matter? More plasma helps our heart pump more blood and oxygen to our working muscles with each beat. As it decreases, our heart eventually has to work a little harder during exercise.

Most of us won’t actually feel a difference for 2–3 weeks.

Translation: Your body noticed your weekend off. You probably didn’t.

After one week: No biggie…unless

Your body begins making tiny adjustments. While it’s not a meaningful decline, this detail is important: Not exercising and not moving are two different things.

Strolling the neighborhood counts. Gardening counts, Groceries shopping counts. Chasing a toddler counts. Carrying a newborn around the house counts.

We talk a lot about the hour we spend working out, but what we do (and eat) during the other 23 hours matters too.

The irony is I am pretty sure that I spent less time sitting last week than I do during a normal week at home. I am a fitness instructor, but I spend more time than I care to admit sitting. Editing video, writing, and administration details are time consuming, sedentary activities. Thank goodness I have my uniquely effective class to counter balance my lifestyle! 

After two weeks: Muscles start slacking

After two weeks, your muscles can start working a little less efficiently. Research cited by Gordon and Roberts found that muscle-fiber recruitment during exercise can drop by around 13%. In other words, the muscle is still there, but our body isn’t calling as much of it into action. The good news is actual strength has likely not dropped yet.

Another reason to keep those muscles moving: they’re a major player in our metabolism. Our muscles pull glucose from our bloodstream and use it for energy. When we become significantly less active, insulin sensitivity and blood-sugar control can begin changing within just a couple of weeks.

After four weeks: Cardio getting cranky

This is when you may really start to feel a difference in your cardio.

One of our best measurements of cardiovascular fitness is VO₂ max, the maximum amount of oxygen our body can use during intense exercise. I’m happy to share that Mojo is an excellent way to strengthen VO₂ max!

After several weeks without exercise, VO₂ max begins to drop. By four weeks, our blood and plasma volume can decrease as much as 12%.

And why do we care? Cardio fitness strengthens our heart and blood vessels, improves circulation and oxygen delivery, helps regulate blood pressure and blood sugar, and gives us the stamina and energy to do more without getting tired. Higher cardiovascular fitness is also strongly associated with a longer, healthier life.

Translation: Cardio isn’t just about endurance. It’s about keeping our heart, circulation and entire oxygen-delivery system strong.

There is some comfort in that for longtime exercisers. Years of conditioning matter. The fitter we are, the more fitness we may initially lose, but we also have more fitness in reserve.

Around 12 weeks: Strength is losing its grip

After a few months without regularly challenging our muscles, strength and power start to fade.

Why do we care? Muscle supports our bones and joints, improves balance and helps us react quickly when we stumble. And when we challenge our muscles through weight-bearing and resistance exercise, we’re challenging our bones too, helping maintain bone density and protect against osteoporosis.

Strong muscles and bones help us climb stairs, get off the floor, carry groceries and keep doing the things we love.

Six months and beyond: This isn’t a break anymore

At this point, we’re not talking about taking a week off because life got busy. Months without regularly challenging our cardiovascular system and muscles give the body plenty of time to adapt to a lower level of demand.

Cardiovascular capacity declines. Strength declines. Eventually muscle mass declines. Things that once felt easy gradually require more effort.

Stairs get harder. Carrying groceries gets harder. Getting off the floor gets harder. Balance becomes harder to maintain.

And this is where “use it or lose it” becomes much bigger than exercise.

Been away for the summer? Recuperating from an injury? Lost your Mojo?
Whatever pulled you away, don’t waste another minute feeling guilty about it. Just come back.

Our bodies are remarkably responsive. Give them a reason to get stronger again, and they will.

Start where you are
Use what you have
Do what you can
and have some FUN while you’re at it!

The goal isn’t to never miss exercise. It’s to make movement such a permanent part of our lives that when life occasionally pulls us away, we simply come back. No guilt. No punishment. No trying to “make up” for missed workouts.

Just keep moving.