FOr, to improve speed, strength, and power in bite-sized workout sessions, there’s nothing like high-intensity interval training (HIIT). These short and sweet sessions pack a punch in just 10-15 minutes and will boost your metabolism, improve your speed and endurance, and improve your overall fitness.
But like any intense exercise, HIIT puts stress on your body, and if done too often or without proper recovery, it can negatively impact hormones like cortisol. Here, experts share how to optimize your HIIT sessions for maximum fitness gains and when to relax.
First things first, what is HIIT?
As the name suggests, high-intensity interval training is exercise that alternates short periods of intense activity, followed by short periods of rest or active recovery. When performed at an ideal heart rate (typically 70-90% of maximum), these high-intensity intervals quickly raise your heart rate, increasing metabolic efficiency, while improving cardiovascular fitness and strength. says Julia Caban, CPT. San Diego.
HIIT is a staple workout at popular national fitness chains like Bally’s and Orangetheory Fitness, but it can be incorporated into any type of physical activity, including cycling, circuit training, and running. And unlike a steady-state workout, which involves a 30-minute or longer cardio session at 50-60% of your maximum heart rate, HIIT can be done in as little as 10 minutes, giving you maximum effort with minimal effort. You can get fitness effects. time. Plus, HIIT is a great way to incorporate fun and varied movements into your regular workout routine, like sprint intervals, jumping jacks, and stair climbing.
Now, what is cortisol?
According to Dr. Sharon Horesh Bergquist, an Atlanta internist, cortisol is a hormone that plays a key role in the body’s stress response. “When the body senses danger, the brain signals the adrenal glands to produce cortisol, which mobilizes the body to respond to the threat,” she explains. Dr. Bergquist says that intense exercise like HIIT can increase cortisol levels in the body, but lifestyle factors such as illness, infection, pregnancy, lack of sleep, and certain medications like steroids can increase them as well. states that it is possible.
Short bursts of intense physical activity like HIIT cause cortisol levels to spike, but “over time the body becomes more resilient and able to adapt to stress, so it’s a good kind of physiological stress.” ,” explains Cavan. This adaptability means your body and mind are ready to handle everyday stressors, whether you’re tackling a difficult work presentation or climbing a steep hill on a weekend hike.
What is the relationship between HIIT and cortisol?
Like other types of high-heart-rate exercise, HIIT increases cortisol because “the body perceives the activity as a form of stress,” Dr. Bergquist says. “In general, the more intense and longer the interval, the greater the increase in cortisol,” she continues.
But that’s not necessarily a bad thing, says Hannah Davis, personal trainer, CPT, CSCS, owner of Body by Hannah in Cleveland, Tennessee. “These exercise-induced cortisol spikes can actually improve your metabolism in the long term and help with overall hormonal regulation and stress management,” she explains.
Dr. Bergquist agrees. “Unlike chronic stress, the cortisol spike from HIIT is short-lived, typically peaking in about 30 minutes and returning to baseline within two hours after training,” she explains. “This short period of intermittent stress triggers a healthy, adaptive response in the body.”
In other words, a temporary spike in cortisol can make your body healthier and more resilient over time, lowering your baseline cortisol levels. This is because HIIT teaches your body (and brain) how to handle physical and psychological stress.
Signs of high cortisol levels
According to Dr. Bergquist, intense exercise without proper recovery, sleep, and eating can increase cortisol levels. The same goes for long-term mental stress, anxiety, and illness. That stress manifests itself in the body as symptoms such as weight gain, abdominal stretch marks, increased blood sugar levels, and high blood pressure.
Medically, the “normal” range for cortisol as measured by traditional blood tests is 5 to 25 mcg/dL (micrograms per deciliter). “When cortisol is outside the normal range of laboratory standards, it usually indicates a specific problem, such as Cushing’s disease or an adrenal condition,” Dr. Bergquist explains. Therefore, if your cortisol levels are higher than normal, she recommends talking to your doctor for a proper diagnosis and treatment plan.
But Dr. Bergquist says current medical blood tests only give a snapshot of cortisol at a single point in time. “In the case of chronic stress, what’s really important is to measure cumulative exposure to high cortisol, and we don’t currently have the ability to measure this directly,” she explains. Therefore, as with any other type of exercise program, it is best to consult your doctor before starting HIIT or if you experience symptoms of high cortisol.
When done properly and supporting optimal recovery, regular HIIT exercises are one of the best forms of exercise.
Who is most susceptible to increased cortisol levels when doing HIIT?
In most healthy people, HIIT causes a temporary increase in cortisol, which decreases after a period of rest. However, if you’re new to HIIT or cardio in general, your cortisol levels can stay high for a long time. The same is true for people who experience chronic stress, lack of sleep, and eat a diet high in sugar or caffeine. “Because their stress system is already activated,” Dr. Bergquist says.
“For people with high cortisol, we recommend starting with low-to-moderate-intensity exercise, such as yoga, strength training, or walking, and gradually increasing the intensity.” Establish basic aerobic conditioning Then, “there will be less of a cortisol spike during HIIT,” she continues.
At the same time, she makes sure that she gets seven to nine hours of sleep a night, eats enough protein to support muscle growth, and enriches her glycogen stores and phytochemicals (chemicals produced by plants). We suggest doubling down on strategic recovery methods, such as eating quality carbohydrates to replenish your diet. May prevent the formation of carcinogens) reduce inflammation and replenish fluids and electrolytes.
“Gentle exercise, such as walking or yoga, can also speed recovery,” she says.
How do you know how much HIIT to do?
How many times a week do you do HIIT?
HIIT is a fun workout that gets your heart rate up, but Davis says it’s best done as part of a comprehensive fitness program that includes active recovery, steady-state cardio, and weight training.
Dr. Berquist recommends that people with normal cortisol levels do HIIT at least once a week, and at most three times a week. As a general rule, HIIT training shouldn’t make up more than 20 percent of your total weekly cardiovascular exercise, Cavan says. “This volume will help you experience the positive benefits of HIIT without the risk of overtraining,” she says.
How many minutes per HIIT session?
One of the benefits of HIIT is that it is a highly effective workout that requires no equipment and can be performed in just 10 minutes. The length of a HIIT workout will vary depending on your fitness level and goals, but 20 to 30 minutes is optimal for building muscle strength and cardiovascular endurance, Cavan says.
Recovery method
When it comes to HIIT, more isn’t necessarily better. “Most people should avoid doing HIIT on consecutive days to allow for proper recovery, especially since it can take up to 24 hours for cortisol levels to return to baseline after a session. Because of that,” Davis says. Recovery time is critical to repairing your muscles and reaping the benefits of becoming “physically stronger and more resistant to stress over time,” says Dr. Bergquist.
To maximize recovery, Caban prioritizes protein intake (at least 0.8g per pound of body weight), 8 to 9 hours of sleep each night, hydration, and enough calories to support your training. We recommend that you do so.
“Unfortunately, HIIT has a bad reputation, and many people who could benefit from it avoid it altogether,” says Davis. She suggests using a fitness tracker or smartwatch to monitor your heart rate during high-intensity activities to ensure you’re hitting the right intensity zone while adhering to prescribed rest periods. .
“People who are negatively affected by HIIT are more likely to not be doing HIIT at all, and are doing high-intensity strength training with lighter loads and more reps without proper recovery. It’s very possible,” Davis continues.
But when done properly and with optimal recovery supported, regular HIIT practice is the best way to not only build muscle strength and endurance, but also improve overall hormonal and mental health. It is one of the forms of exercise.
