FOR MOST OF US, the word “stress” brings to mind the teeth-grinding agita that overtakes us in a traffic jam or during a panicky day at the office. We consider it our health enemy, right along with smoking, sitting, and sugar. But stress can be positive, say some wellness-minded types who embrace “hormetic stress.” Hor-what? It’s basically a way to push yourself out of your comfort zone in order to get stronger, biologically speaking. (Hormesis, from the Greek word for “excite,” refers to a process in which a small dose of something harmful may have a beneficial effect.) By gently subjecting the body to mild discomfort—cold, heat, spurts of intense activity, limited fasting—followed by recovery, we can promote resilience, metabolic health, and longevity. The idea is gaining popularity, which is why you may have seen Harry Styles sitting in an ice bath on Instagram.
Though the practice might sound a bit out there, the science seems promising, says Ryo Sanabria, PhD, assistant professor of gerontology at the USC Leonard Davis School of Gerontology, who studies the link between stress and aging. “Researchers have started to see that low-grade stress that’s not damaging to the body can be beneficial,” he says. “It causes an adaptive response of cells and organisms.”
How it works: Among other physiological changes, encountering stressors activates the secretion of cortisol and adrenaline, which leads to increased heart rate and blood pressure. In cases of chronic stress (the kind that simmers inside us long-term), a prolonged bodily response can be harmful. With hormetic stress, however, we rest and recover quickly, leaving us potentially more resilient to future stress and at less risk of disease. Think of what happens when you lift weights: You get tiny tears in your muscles that might not feel so good the next day, but when they eventually heal, you’re ready for heavier dumbbells.
While research into the practice is in its early days, it might be worth trying, as a way to help improve your immunity. (Just talk to your doctor first, especially if you have a heart condition or other chronic medical issues.) Here, four ways to get stressed-out.
WHAT IT IS Yikes! If you’ve ever unintentionally stepped into a chilly shower, you may have gotten an unpleasant shock. Well, some people are doing this on purpose—putting not only their toes but their entire bodies in water that’s below 60°F, with experienced bathers going as low as 40°F. Cold showers, polar bear plunges, and icy swims are among the most popular ways to trigger good stress right now. For a real flex, you can even have a cold tub installed in your house or yard: Some humble models that look like gigantic buckets cost $100 or less.
POTENTIAL PERKS Exposing the body to cold activates our thermoregulation as we try to maintain our internal temperature, explains Molly Maloof, MD, author of The Spark Factor: The Secret to Supercharging Energy, Becoming Resilient, and Feeling Better Than Ever. “In the process, we release certain hormones and proteins that help improve cardiovascular function, immune response, and cellular repair,” she says. “It also enhances circulation and metabolism.”
And though an ice bath might not sound like a post workout treat, it can help with joint and muscle recovery, says Thomas M. Holland, MD, a clinician and researcher at the Rush Institute for Healthy Aging in Chicago. “Cold decreases inflammation and causes vasoconstriction,” a narrowing of the blood vessels that may help the body rid itself of lactic acid and other waste products that contribute to muscle soreness. An ice plunge may also be a mood booster, flooding your body with “happy” chemicals, like dopamine and serotonin. One Czech study found that subjects immersed in a 57°F bath enjoyed a 250% increase in dopamine.
TRY IT Start with 30-second cold spurts in your shower, working your way up to two minutes, Maloof recommends. If you want to try an ice bath, the water should be between 50°F and 59°F (a baby-bath thermometer comes in handy here). It’s fine if a 30-second dip is all you can handle at first, though the ideal soak time is between 2 and 10 minutes, Holland says. Cautionary note: Cold immersion causes your heart rate and blood pressure to increase rapidly (and potentially dangerously), so again, check with your doctor first. And start slow.
WHAT IT IS You’ve probably already done this one, if you’ve ever soaked in a hot tub or sat in a sauna or steam room. You may have felt relaxed, but your body was actually undergoing hormetic stress.
POTENTIAL PERKS Heat therapy works much like cold therapy—just in reverse. As your thermoregulation system cools down your core temperature, you experience vasodilation, an expansion of the blood vessels, increasing circulation, Holland explains. The greater blood flow provides a rush of oxygen and nutrients to tissues, soothing sore or stiff joints, he says. Your heart also has to work harder to support this extra blood flow (more good stress). Heat therapy is currently being considered for treatment of neurodegenerative diseases, such as Alzheimer’s, Sanabria adds. “When cells get stressed, certain genes turn on like switches,” he says. So if you’re hot on a 100°F day, genes that protect the body from heat will turn on. Surprisingly, the switches that relieve heat stress may also help the brain clear away proteins that harm its cells.
TRY IT Sit in a sauna or steam room for 20 minutes a few days a week, Maloof says. Or soak in a hot tub. No access? Crank your shower to its hottest setting, put a rolled towel under the bathroom door to trap heat, and enjoy a DIY steam. Saunas and hot tubs can bring down your blood pressure, so if yours is already low, ask your doc if this is OK to try. And drink plenty of water before, during, and after to replenish the fluids you lost with all that sweating. If you feel any weirdness—dizziness, confusion, tunnel vision—move to room temp immediately or get medical care.
WHAT IT IS Known as HIIT, these workouts alternate short bursts of intense exercise with periods of rest. It’s associated with the jock crowd, but any routine, like walking or biking, can become a HIIT workout.
POTENTIAL PERKS The fast-and-slow process is great for muscle strength and endurance—possibly better than traditional cardio, suggests a recent meta-analysis of 19 studies in the International Journal of Environmental Research and Public Health. “HIIT stresses the cardiovascular and musculoskeletal systems, leading to adaptations that improve endurance, strength, and metabolic efficiency,” Maloof says. The intensity of HIIT also sends your heart rate soaring and burns through your blood sugar, Holland notes.
TRY IT Start slow, with a 1:3 ratio of bursts and breaks (for instance, 15 seconds of intense activity followed by 45 seconds of rest) for 15 or 20 minutes total, Holland says. The intense activity can be walking extra briskly, as long as you get your heart pumping. Incorporate HIIT into your routine once a week, Maloof says. Any more can be too much for a beginner’s body. Talk to your doctor if you’re taking medications that affect blood pressure or heart rate, Holland says. And pay attention to your body: Breathing hard is one thing, but feeling close to passing out is another.
WHAT IT IS This eating strategy, called IF for short, involves limiting your daily food intake to a specific window of time. While there are many ways to do IF, the 16:8 model is a popular one. You fast for 16 hours (you’re ideally sleeping for about half of that time anyway) and eat your meals and snacks during the remaining eight. You can choose whatever eight-hour window you prefer; many people skip breakfast and eat lunch around noon, finishing dinner by 8 p.m.
POTENTIAL PERKS IF can help with weight loss, if that’s your goal, but it has other benefits too, like lowering insulin resistance and reducing blood pressure and cholesterol levels, says Krista Varady, PhD, professor of nutrition at the University of Illinois Chicago. It’s also said to help quash inflammation, which could help reduce your risk of chronic conditions like diabetes and heart disease, but more studies need to be done.
TRY IT Ease into IF by doing it for a day or two. No one wants to be hangry, so to stay satiated during your fasting period, your best bet is to go low-carb and consume plenty of fat and protein during your eight-hour eating window. If you have a history of an eating disorder, IF is likely not safe for you. And anyone with diabetes should check with their doctor to see if they need to adjust their medication schedule. Lastly, as always, don’t forget to stay hydrated. Water can help with that chronic stress too!