- In an excerpt from his new book 4-Minute Fit: The Metabolism Accelerator for the Time Crunched, Deskbound, and Stressed-Out, Siphiwe Baleka details how sleep affects the efficiency and effectiveness of your metabolism.
The following is excerpted from 4-MINUTE FIT: The Metabolism Accelerator for the Time Crunched, Deskbound, and Stressed-Out by Siphiwe Baleka with L. Jon Wertheim. Copyright © 2017 by Siphiwe Baleka and Jon Wertheim. Reprinted with permission from Touchstone, a Division of Simon & Schuster, Inc.
Metabolism is a complicated concept, but here’s how I like to simplify it: metabolism is the process for producing energy in the body.
People who are obese, who are sedentary, whose work schedules interfere with their circadian rhythms and sleep schedules, or who are under a lot of stress, all face the same issue: they have inefficient metabolisms. All of this is totally understandable for reasons I’ll explain below. But if you fall into this category, the immediate goal should be making your metabolism more efficient and more effective.
How do we do that? Well, let’s start at the cellular level. Energy is produced in a specific place inside of every cell, the mitochondria. And in order to produce energy, the mitochondria need what’s called adenosine triphosphate (ATP) for fuel. The more mitochondria you have and the bigger the mitochondria you have, the more potential capacity you have to produce energy, and the higher your overall metabolism (and daily calorie burn) will be. Think of mitochondria as the burners on your grill: the more you have, and the higher they’re cranked up, the more energy you’ll burn off every single minute of the day.
So 4-Minute Fit is designed to address the issues that inhibit the production of ATP, causing us to create energy inefficiently and hence become slower, fatter, hungrier, and more tired. Our goal is to muscle up your mitochondria! Here’s how we do it.
Better Metabolism Through Sleep
Your metabolism and energy cycles are controlled by a complex series of hormones. Again, I like to describe hormones as signals in the body that stimulate processes and get us to act. You haven’t eaten in a while? Your body will send you signals saying that you need some raw materials (i.e., food) to produce fuel. That’s a signal from the “hunger hormone” ghrelin, which is produced in your sleep. The hormone is secreted, it triggers you to eat, and that’s the way to ensure that you have the raw materials for energy production. When your ghrelin is high, we get hungry and crave “unhealthy” foods. When your ghrelin is low, hunger decreases. Meanwhile, the hormone leptin regulates the signal that tells you to stop eating. What happens when you go to fill up your car or truck with gas, you leave the gas pump nozzle in the fuel tank, and you put it on automatic? If there’s no automatic switch to stop, the tank overflows, right? Same with the body and food. You need a signal to tell you when you need to stop inserting fuel.
Leptin is also produced during sleep, and in combination with ghrelin, is a primary driver of metabolism. And if you’re not getting enough sleep, you’re not producing these hormones in the right amounts, so you lose the ability to properly regulate metabolism.
In the case of truckers, the shifts are irregular, and their schedules are compounded by time pressure. Thanks to these factors, truckers average only 4.78 hours of sleep per 24 hours. As a result, they’re not producing the hormones to regulate metabolism properly. So the majority of drivers are not getting the signals that they need to eat. (The National Sleep Foundation recommends between 7 and 9 hours of sleep for the average adult, though about 43% of us get less than that on a regular basis.)
On the average, truckers eat only 2.6 times per day, often skipping entire meals, sometimes to the point that they’re technically malnourished. But when they do eat, they often overeat. Why? Primarily as a function of hormones. They’re not hungry because their ghrelin levels are low and they’re not getting the signal that says You’re hungry and need to eat. But they do eat, and they’re not getting signaled that they need to stop, because their leptin levels are low. Because those hormones are produced in sleep and the truckers are sleep-deprived, their hormones are affected.
So sleep—not diet—is actually the root of the problem. Bottom line: you don’t sleep properly, you’re not going to regulate your food intake properly.
My Metabolic Sleep Adventure
When I first started tracking my sleep, I was getting around 6 hours and 15 minutes each night. My sleep scores—an index for the quality of sleep—were around 60-70%. The digital health technology told me exactly where I was on a scale from zero to optimal. It was then up to me to improve.
As I stated above, nearly half of us are chronically sleep deprived. But I don’t want to be in this group, and I don’t want to do anything in life at 60-70% of my potential. So then the question became, “If this is where I am, what do I have to do to get better?”
I read up on sleep hygiene and came up with ways to try to improve both the quality and quantity. This became clear first: I needed to “respect the sleep environment.” This means different things for different people. For me, it meant reserving my bedroom for sleep. I didn’t watch TV in there, didn’t exercise in there. I wanted my mind and body to associate my bedroom with sleeping. I’m here; now it’s time to sleep.
Next, I tried to block out all the light possible. I put up curtains and made sure that no lights—not even lights from the phone—were left on. As you know, I’m a huge advocate of technology—everywhere but the bedroom. I removed all electronic devices from my bedside. My alarm clock was battery powered.
Hard as it was, I even made sure to leave my cell phone far from the bed. Turns out, this is a big issue right now. (With no end in sight.) Researchers say that it’s almost as though the smartphone is designed ideally to disrupt our sleep. Some of this is psychological. We all need to disengage when we sleep. But when your phone is within arm’s reach as you sleep, you will still feel connected—to work, to your social life, to Facebook.
It’s physiological, too, though. Melatonin is the hormone that promotes sleep; when you expose yourself to the light emitted by your smartphone, it inhibits melatonin.
Sleep is another example of your body being connected to your environment. The body picks up on signals from your surroundings. This isn’t new. Before electricity, when the sun set and the temperatures cooled and atmospheric changes occurred at night, these all sent signals to our bodies to secrete serotonin and melatonin and signal that it was time to rest. Darkness was not conducive to human activity; it was conducive to sleeping!
If you want to get good at anything, what’s the fastest and most effective way to achieve the goal? Do it consistently, build a routine. Same for sleeping. I realized that if I undertook the same routines and fell asleep at the same time every day, it would help. I power down my electronics about an hour before bedtime. I drink a small cup of chamomile tea. I read a book, but usually get through only a few pages before I am out.
Using a sleep tracker, I made sure to keep the same bedtime and then look at the data each week to let me know how I was doing. Same for waking up. If you rise at the same time, your body will crave the routine. So often we get up at the same time each day and soon discover our bodies don’t even require the alarm clock.
Now, I sleep between 7.2 and 7.4 hours a night. My sleep onset latency is roughly 12 minutes—that is, I fall asleep and lose wakefulness 12 minutes after my head hits the bed. My sleep index is now more than 90% of optimal. Not perfect yet. But I’m still working on it.
Better Metabolism Through Exercise
If you exercise for sixty minutes at a moderate level, that long exertion over a long period has an effect on your serum ghrelin, triggering production of the hormone. This is why you feel famished after you, say, play a three-set tennis match or go for a long run. Studies will show, for example, that people who exercise for 50 minutes will burn an extra 200 to 300 calories, but they also eat an extra 200 to 300 calories.
On the other hand, when you exercise according to 4-Minute Fit, limiting yourself to no more than 15 minutes of working out, it’s a short enough interval that it doesn’t stimulate the production of ghrelin. You won’t feel hungry. What’s more, shorter, more intense workouts can affect your other hormones in ways that are going to make you sleep better. When you sleep better, you produce the correct levels of leptin and ghrelin, you regulate metabolism and hunger better, and then you eat better or more regularly, and that brings you back into harmony. It’s a spiral of good effects.
To understand fully the benefits of vigorous activity, it is important to know this: there is a difference between weight-loss thinking and fat-loss thinking. Weight-loss thinking makes calorie-burning the goal.
Fat-loss thinking is all about hormones. Most people exercise because they believe that burning more calories is the way to lose weight. This is part of the “eat less, exercise more” approach.
But when we exercise more, the natural compensatory reaction of the body is to eat more, while also slowing the metabolic processes in other aspects of our daily lives, frustrating our weight-loss efforts. And when we exercise less, the body responds by suppressing appetite, which keeps our metabolism at a low level, further frustrating our weight-loss attempts. Again, this is due to the action of leptin and ghrelin. Leptin is produced in the fat cells: as soon as you start losing weight (fat), your falling leptin levels signal your body to start eating more and slow down your metabolic fat-burning, causing you to hold on to that fat.
Rising leptin levels do the opposite: they shut off hunger and stimulate metabolism. In normal-weight people, this works to maintain normal bodyweight—you gain a little fat, your leptin rises, signaling your body to stop eating so much.
However, in obese people, this mechanism often goes haywire. As we gain weight, our leptin levels increase. But if our metabolisms are already compromised—by a lack of sleep, by too many carbohydrates, by too much stress, or by unhealthy eating schedules—we continue to pack on pounds. When leptin levels are very high for long periods (which often coincides with obesity), leptin resistance sets in—the body no longer responds to the cue to stimulate metabolism. This means very high leptin levels can cause both increased hunger and slowed metabolism. This is the common perception of obese people—they just eat and eat and eat while their metabolism gets slower and slower.
Now, remember what we learned about mitochondria and the creation of ATP? When we use brief bouts of intense, muscle-producing exercise, we create a maximum demand for energy; the muscles are requiring so much energy that the mitochondria have to operate at full capacity. Meaning they have to use as much ATP as possible in as many cells as possible. The more muscles you use at maximum intensity, the greater the demand for ATP. And the body must create more and bigger mitochondria to answer that demand. Bam! You’ve just reset your metabolism.
Testimonial: “You tell me if it works”
One time I was standing in front of a mirror at a Petro truck stop in Nevada doing my exercises. To the side, to the side, kick your leg up. Just then another female trucker walked in, glared, walked out, and called the manager in to gripe. The manager came by but explained that I could use the mirror however I wanted. So the woman asks me, “What are you doing, anyway?”
“My daily exercise,” I said.
“How’s that work exactly?” she wondered, now getting curious.
“I’m trying to stay healthy, doing the best I can, when I can,” I said. “My heart rate will go up, and when I get back in the truck my metabolism will be a little higher.”
“Well, has it worked?” the woman asked.
I told her I lost weight and cut down my medication for diabetes. I feel better and have more energy. I said, “Honey, you tell me if that sounds like it works.”
—Yvonne Johnson, nineteen-year-veteran truck driver
The Metabolism "Spike"
I’ve talked a lot about the importance of “spiking” metabolism in the first few chapters. Now I’ve shown you how creating those metabolic spikes forces your body to create more and larger mitochondria, setting you up for a higher day-long metabolism and greater all-day calorie burn.
We track these metabolic spikes through a measurement called metabolic equivalents, or METs. One MET represents the amount of oxygen you consume and the number of calories you burn at rest. If you see, say, 7 METs on a treadmill, it represents your working 7 times as hard as you would be at rest, consuming 7 times as much oxygen, and burning 7 times as many calories as you would be at rest.
As a rule of thumb:
0 to 3 METs: light activity
3 to 6 METs: moderate activity
6 or more METs: vigorous activity
The people who don’t exercise? Whose extent of bodily movement is easing in and out of a truck or getting in and out of their car at the office? They’re only spiking their metabolism to just over 3 METs, maybe 4 if they’re lucky and walk really fast.
So the people doing nothing, no exercise? Their METs are in sedentary position for the vast majority of the day, easily 23 hours, probably closer to 23:30. And it goes above the sedentary mark only when they walk, and even that yields only 3 or 4 METs, not even the middle of the moderate zone. This is a very slow, or low, metabolism. This will probably sound harsh, but they have the metabolism of a cow. Think about it: a cow or a slow-moving mammal that has a really low metabolism.
The people doing the four minutes of exercise? For those four minutes, their metabolism goes from 1 to a level in the 6+ range. That puts an incredible demand on their fat-burning system, sparking the need for more ATP. And, like many things in life, when you use it to its full potential, it adapts and grows and gets stronger—in this case, through the increase in mitochondria. So the person doing nothing isn’t challenging his metabolism; the person doing four minutes of exercise is. If you’re getting 6.3 METs one week, odds are good you’ll work comparably hard and be at 6.4 METs the next week. Every week, you are improving your metabolism.
But just because you have more ATP, and a greater capacity to use it, you aren’t necessarily going to produce more energy. You need to have enough of the proper fuel to produce that energy. And that’s why the dietary component of this program—reducing carbs and boosting protein—is also essential.
The Metabolic Consequence
At Prime, I studied how the lack of metabolic spikes affected drivers’ body composition, looking at both male and female drivers, their ages, and their years of driving experience. The data shows that for men and women combined, the average BMI increases from 32.05 in the first sixty days of one’s driving career and reaches a peak of 35.79 within three years. During this time, for men, their visceral fat rating—measure of the amount of fat surrounding the internal organs—increases from 14.7 in the first six months of driving to an average of 16.77 by the end of the third year. Consider: a visceral fat rating of 12 or less is considered normal and healthy.
For men, the older you are, the higher the average visceral fat rating, too. So if you start your driving career later in life, you are more likely to gain more abdominal fat in the first three years of driving. Male drivers between fifty-five and fifty-nine have the highest BMI of any age group (33.8), while female drivers between fifty-one and fifty-five have the highest BMI (35.93) for their gender’s age group range. Visceral fat ratings for those groups are 17.95 and 11.38, respectively.
When you live a sedentary existence, as most of us are forced to do, just four minutes of vigorous activity a day can change your metabolic capacity. Without those four minutes, the consequences are inescapable.