4 Reasons That You Need To Sleep If You Want To Get In Shape

Sleep is as important as diet and exercise in supporting your fitness goals

If I told you that I was implementing a fitness regimen to get in the best shape of my life but wasn’t doing any physical exercise, what would your reaction be?

How about If I told you that I wanted to get a shredded 6-pack for summer, but that my diet consisted entirely of Twinkies and Cheetos. How would you respond?

My guess is that you would laugh in my face, or perhaps you would refrain since you’d assume I was severely challenged and you wouldn’t want to appear rude.

But now imagine that I told you about my plan to get in the best shape in my life in a 12-week transformation program, but that my work life and family responsibilities were especially taxing, and that I was only able to get 5 hours of sleep per night.

What would your reaction be? This time I’d expect that it would be one of respect for my work ethic instead of confusion and ridicule.

The discrepancy between your hypothetical reactions in these circumstances is not supported by science: Sleep is a foundational pillar in our health and well-being, and it is especially important when we’re trying to improve our health and get in shape.

While the importance of sleep has gained recognition recently (especially due to Matthew Walker’s best-selling book “Why We Sleep”) it is still nowhere close to being perceived with the same level of importance to our well-being as diet and exercise.

As someone who is moderately obsessed with fitness, I want to share a few of the most profound facts I’ve learned that pertain to the importance of sleep for getting (and staying) in shape. There is strong evidence to support the claim that sleep deserves the same amount of respect as diet and exercise as it applies to our fitness goals.

Your Heart Likes to Sleep

The evidence that low sleep is harmful to your heart and cardiovascular system is overwhelming. Poor sleep causes a rise in blood pressure, and it doesn’t take weeks of sleep loss for this to occur. A single night of insufficient sleep (around 4 hours) is all that is required to increase blood pressure(1). This occurs in a wide age range and affects fit and healthy people.

It is not only heart rate and blood pressure that are impacted by sleep loss. Atherosclerosis is the underlying cause of approximately 50% of deaths in Western Society(2), and routinely getting less than 6 hours of sleep can significantly increase the likelihood that you’ll get it. This study from the University of Chicago found that sleeping over 7 hours per night was shown to decrease the calcification of arteries in people over 40 by over 300%! (3)

Everyone needs a strong and healthy heart. While even those who love to just lift weights may complain about their disdain for doing cardio, they might remind themselves that it is their heart that supplies their muscles with the oxygen needed to put in the work.

It only takes one night of poor sleep to increase blood pressure and heart rate, and this will have a negative impact on athletic performance. As people progress into their 40s and beyond, it is crystal clear that sleeping less than 6 hours per night significantly increases the likelihood of calcification of coronary arteries.

A strong heart requires strong sleep habits.

Low Sleep = Low Testosterone

Testosterone supplements are all the rage. It’s common for men to get excited about the latest root, leaf, or piece of bark that is rumored to increase testosterone and subsequently spend their hard-earned money on it. But there is a very effective testosterone supplement that is completely free, and it’s called GO TO SLEEP.

This point is not only relevant to men — women need and benefit from testosterone as well. There is a reason that it is illegal to supplement with testosterone if you’re a competing athlete — it’s basically a superhuman drug. It supports muscle growth, fat loss, strong bones, improved mood, and a better sex drive.

A 2003 study from the University of Chicago aimed to observe the effects of sleep deprivation on testosterone levels. The study involved 10 men with no history of psychiatric or endocrine disorders. The men had a mean age of 24 years and a mean BMI of 23.5 — it’s safe to say these were fit and healthy young men.

They were instructed to spend a week sleeping 8 hours nightly (from 11 pm to 7 am) at home, and then they spent 11 days in a lab. During the first 3 nights, they were given a 10-hour sleep window, and this was reduced to a 5-hour window for the remaining 8 nights.

Their blood was measured daily, and the findings were that testosterone was decreased by 10–15% in the sleep-restricted state compared to the rested state. (4)

No leaf extract is going to increase your testosterone by 15%. But if you’re sleeping less than 6 hours per night, you stand to gain a lot from providing yourself with some more shut-eye.

Sleep Less to Become Hungrier

If you want that 6-pack for summer, it will be useful for you to give yourself an 8-hour sleep opportunity each night. You can do all the sit-ups and crunches you want, but nobody will see your glorious abs if you can’t maintain a low body-fat level — and the research shows us that if you neglect to give yourself adequate opportunities to sleep, you will be far too hungry to let your abdominals shine.

Dr. Eve Van Cauter has done some fascinating research on sleep and eating habits at the University of Chicago. Her research has found that sleep restriction has a profound effect on the 2 hormones that impact our appetites: Leptin and Ghrelin.

Leptin is a hormone secreted by fat cells, and it is responsible for our feeling of satiety. Ghrelin is secreted by our stomach and sends us signals that it is time to eat.

Low leptin levels combined with high ghrelin levels can easily result in symptoms such as double cheeseburgers, french fries, donuts, chicken strips, and milkshakes.

One of Dr. Van Cauter’s studies involved two groups of 6 men who were observed, questioned, and had their hormones tested after periods of restricted and then extended sleep (in a lab).

The results concluded that sleep restriction was associated with an 18% decrease in leptin and a 24% increase in ghrelin. (5) The subjects also answered that they felt noticeably hungrier and had a desire for processed, sugary snacks following the restricted state.

It can be difficult enough to resist delectable, processed food during ideal circumstances. This becomes much harder when we create an environment for the hormones that regulate appetite to make us much hungrier than we would otherwise be.

Losing Sleep Means Losing Muscle

This is another finding from the illustrious Dr. Eve Van Cauter. Out of all the research on sleep I’ve seen, this finding is the most shocking ( and inspiring to prioritize sleep for fitness!)

In another 2003 study, Dr. Van Cauter recruited 10 overweight nonsmoking adults with a mean age of 41 years. The subjects spent two 14-day periods (separated by at least 3 months) in the lab with a set meal plan that was below their maintenance calories.

The difference between the two periods was that in one instance the subjects had an 8.5-hour sleep window and in the other only a 5.5-hour sleep window. Of course, since calories regulate weight loss, subjects lost weight in both settings. What is fascinating is where the weight came from.

More than half of the weight loss in the rested phases came from fat as opposed to only a quarter during the restricted phase. (6)

The subjects lost more fat and retained lean mass (i.e. muscle) when they were provided with an 8.5-hour sleep opportunity. During the restricted sleep phase, more of their weight loss came from muscle. Looking fit isn’t only about being lean — you need to have visible muscle too. The conclusion that Dr. Van Cauter and her colleagues came to is that if you accompany your diet with a lack of sleep, you’ll be doing your physique a disservice: You’ll be more likely to burn through your muscle stores as opposed to the fat you want to get rid of.

There is a saying amongst hustlers that goes “I’ll sleep when I’m dead.” If you fail to provide time for sleep, you won’t have as long to wait. And while you do wait, you will have a weaker heart, be at a higher risk for atherosclerosis, struggle to build muscle, suffer from decreased libido, and be far hungrier.

These are problems for everyone, but they are especially pertinent for those who are exercising and attempting to improve their fitness.

If you need to get more done, cut out Netflix, mindless scrolling through social media, and video games. But do yourself a favor — don’t cut out sleep. Treat yourself to that 8-hour window per night, the science says that you won’t be disappointed.

1. Effects of insufficient sleep on blood pressure monitored by a new multibiomedical recorder https://pubmed.ncbi.nlm.nih.gov/8641742/

2. Atherosclerosis https://www.ncbi.nlm.nih.gov/books/NBK507799/

3. Skipping Sleep may cause problems for coronary arteries https://www.uchicagomedicine.org/forefront/news/skipping-sleep-may-signal-problems-for-coronary-arteries

4. Effect of 1 Week of Sleep Restriction on Testosterone Levels in Young Healthy Men. https://pubmed.ncbi.nlm.nih.gov/8641742/

5. Sleep loss boosts appetite, may encourage weight gain https://www.uchicagomedicine.org/forefront/news/sleep-loss-boosts-appetite-may-encourage-weight-gain

6. Insufficient sleep undermines dietary efforts to reduce adiposity https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2951287/