Believe it or not, intensive cardio isn’t the best way to lose weight.
In fact, it’s not even the best way to have a healthy body!
Of course, exercise is a necessary pillar of a balanced, healthy body and lifestyle. If you want to be healthy, you absolutely need to exercise regularly.
However, many people overdo it. It’s so common to associate cardio with weight loss that many assume the more they exercise, the healthier they’ll be. And so they become cardio addicts, thinking theyre living hyper-healthy lives.
These people are mistaken. If your exercise routine includes long periods of intensive cardio multiple times a week, you’re overtraining.
As you’ll see, overtraining is just as detrimental to your health as sitting around on the couch all day!
As with anything in life, exercise has a sweet spot. And if you really want to lose weight and live a healthy lifestyle, you need to find that sweet spot.
Let’s take a closer look at exactly how overtraining harms your body and just how much exercise is healthy.
Burning That Sugar
Conventional wisdom suggests 45-60 minutes of intense cardio activity each day. Unfortunately, this “wisdom” is anything but— and it’s hurting people.
Sustained, high-intensity cardio (heart rate in the 80%+ range) is vigorous exercise that leads to extreme spikes in cortisol (the stress hormone) production.
Working out like this consistently is stressful for your body. It leads to chronically high levels of cortisol, which can impair sleep and memory and cause digestive issues, depression, and weight/fat gain.
What’s more, to support this level of high-intensity cardio, your body has to burn sugars (glucose). While this is fine in short bursts, exercising like this for long periods of time (one hour or more) multiple days a week teaches your body to burn sugars for fuel.
To sustain an exercise routine like this would require a daily intake of at least 600g of carbs to refuel the 600g or so of glucose that your muscles and liver can store at any given time. Eating this many carbs produces unhealthy insulin spikes that, over time, can easily lead to systemic inflammation, increased insulin resistance, and a higher risk of diabetes.
A high-carb diet and extreme exercise routine also lead to decreased fat metabolism, increased oxidative damage, and weakened, damaged muscles and joints.
The immune system is also affected by overtraining. Sustained high-intensity exercise causes the immune system to become hyperactive, which overall impairs its performance. This can lead to the development of autoimmune disorders, chronic fatigue, decreased appetite, and changes in sleep.
Studies have shown that overtraining can also lead to depression and chronic fatigue by inhibiting the production of important neurotransmitters like glutamine, dopamine, and 5-HTP.
Getting the Feels
It’s well-known that long periods of cardio can lead to the release of a cascade of pleasurable hormones. I’m sure you’ve heard of the “runner’s high” phenomenon. I’ve experienced it myself a few times, and it’s wonderful! It’s easy to see why people enjoy long runs or bike rides.
However, overtraining can lead to overworked, stressed-out hormone centers, especially the thyroid and adrenal glands. Overtaxed hormone centers can cause a lot of problems to your health.
Overtraining often leads to hyperthyroidism, a disorder characterized by an underactive thyroid gland that fails to properly produce hormones.
Hyperthyroidism can lead to many unpleasant symptoms, such as depression, anxiety, infertility, fatigue, weight gain, digestive issues, and lowered immune function.
Too much exercise can also lead to dysfunction of the hypothalamic-pituitary axis. This axis is often referred to as your body’s hormone “control center.” It affects the thyroid gland, adrenal glands, and ovaries or testes.
Hypothalamic-pituitary gland dysfunction can impact calorie intake, weight regulation, body heat, and your body’s response to stress.
Needless to say, you don’t want to negatively impact your body’s hormone centers!
Slow It Down
Believe it or not, the best way to lose weight is to slow down.
Mark Sisson is a big advocate of this more primal approach. He recommends modeling our exercise routines after our cavemen ancestors, who spent many hours a day doing low-level activity (walking, gathering, etc.) and only occasionally engaged in bursts of intense activity (hunting, escaping predators, etc.).
A healthier, more primal exercise routine would focus on low- to moderate-level aerobic activity, with only occasional sessions of intense activity.
For example, 30-60 minutes of brisk walking, hiking, or cycling at least a few times a week. Lower-level activity, where your heart rate stays in the 60-70% range, is ideal for burning fat, lowering blood pressure, increasing the capillary network, and reducing the risk of serious health issues like heart disease.
It also builds your aerobic capacity slowly, increases muscle mitochondria (the main source of energy production in your muscle cells), doesn’t overstress your body’s hormone centers or immune system, and trains your body to use fat as fuel instead of sugars.
These slower sessions should be interspersed with more intense “interval” training sessions, such as weightlifting or 20-40 seconds of all-out sprints. High-intensity training also has many health benefits when not overdone!
Sprints and strength training also increase muscle mitochondria. They build lean muscle mass, support healthy growth hormone production, and increase aerobic capacity (basically, how much you can exercise before feeling winded), muscle fiber strength, and insulin sensitivity (which decreases the risk of diabetes).
It’s not going to kill you to go all-out in the gym sometimes— just don’t do so every day! Chris Kresser recommends you limit high-intensity workouts to two or three times a week and mix up your routine with slower, less stressful forms of exercise, like walking, hiking, or yoga.
If your goals include anti-aging, longevity, and balanced, excellent health, your way forward is clear.
Avoid consistent high-intensity exercise, as it will stress and overwhelm your system.
Of course, don’t give up exercise altogether! That would be just as bad for your health as overtraining.
For a healthy, happy body, your best bet is to slow down, focus on low- or moderate-level activity, and only occasionally engage in high-intensity training.
As always, listen to your body. It will help you find that exercise sweet spot.