Jan. 6, 2022 — Doctors have been encouraged in recent years to treat exercise as medicine, telling their patients how often, how long and how hard to exercise to improve health .
A new study from Brigham Young University suggests that doctors can take that initiative to the next level, prescribing exercise plans that result in a specific health outcome; Say, lowering your blood pressure or losing weight.
“The findings of this study, and others, suggest that we should be able to more consistently and accurately prescribe exercise like medicine,” says senior study author Jason Gifford, PhD, professor of exercise science at BYU.
These exercise prescriptions will be tailored to patients based on a largely neglected fitness measure called critical power, or maximum steady state — the speed at which you can sustain for long periods of time.
By building workouts around vital power, rather than the more frequently used VO2 max (maximal effort), we can more accurately predict health outcomes than we can with medication, researchers say Journal of Applied Physiology,
“We’ve known for centuries that exercise is part of the way to develop a healthy and long life,” says Jordan Metzl, MD, a sports medicine doctor at the Hospital for Special Surgery in New York and author. exercise therapy, “But it is only in the last 70 years that we have recognized the medicinal value of exercise.”
Metzl, who was not involved in the study, helped develop an annual symposium at Cornell Medical School to teach medical students how to exercise beyond the “30 minutes a day” cookie-cutter advice. Nevertheless, doctors and other health care professionals struggle to exercise often To prevent or treat disease. and a Recent Studies from Oxford found that when doctors recommend weight loss, It is often unclear and difficult for patients to use.
“Movement medicine is one of the safest and most effective forms of preventive health,” says Metzl. “We need to fully involve the medical community in prescribing exercise for our patients.”
This study shows that focused attention can be a key force in making this happen.
what the research found
In the study, 22 adults completed 8 weeks of either moderate-intensity training or high-intensity interval training, or HIIT. The intensity levels specified in both plans were based on VO2 max. Therefore, the subjects in the study trained at a given percentage of their VO2 max.
Both groups saw improvements in endurance, but results varied greatly from person to person. Those mixed results may be explained by individual differences in vital power.
Lead study author Jessica Collins, a researcher at Brigham Young University, says, “The improvement was highly correlated with the percentage of vital forces they worked, rather than the percentage of their VO2 max, as exercise physiologists have thought for years. ”
Not only that, but many subjects who did not improve their VO2 max did See significant strength and endurance increases.
“People only focus on VO2 max,” says Gifford. “Many people may see a lack of increase in VO2 max for some people and conclude that the training was ineffective. I personally believe that the almost exclusive focus on VO2 max has led to many potentially useful treatments being dismissed. has given.
Turns out, vital power varies greatly from person to person, even among people with similar VO2 max.
“Let’s say you and Jessica had the same VO2 max,” explains Gifford. “If we were both going at 70% [your VO2 max]It could have been above Your maximum stable state, which will make it really difficult for you. and it can be Down His maximum stable state, which would make it easier for him.
This means you’re each stressing your body differently, and that stress triggers improvements in fitness and endurance.
“Below critical strength, metabolic stress is well managed and maintained at an elevated-but-stable level,” says Gifford. “Above critical strength, metabolic stresses are generated so rapidly that they cannot be controlled, and accrue continuously until reaching levels high enough to cause failure.”
Knowing your vital power means you can anticipate where those stresses will build up, and you can design an exercise program that delivers the right stress “dose” for you, Gifford says.
Such programs could be used to rehab patients recovering from heart attacks or lung disease, Gifford suggests. Or they may help older adults improve stamina and physical function, Collins notes.
But first, researchers must confirm these results by programming workouts based on people’s vital strength and seeing how much the various measures improved.
How to find your critical power
Critical power is nothing new, but it has been largely ignored by exercise physiologists and medical professionals because it is not easy to measure.
“People usually train at VO2 max or max heart rate, which is less accurate,” says Gifford.
The study involved multiple time trials to find people’s vital power and calculated the relationship between speed/power and time, Gifford explains.
But for a rough measurement of your vital power, you can use an app that measures functional threshold power (FTP), something Giffords refers to as the “Walmart version” of vital power. “It’s not exactly the same, but it’s close,” he says. (App Strava FTP has a very sophisticated power analysis feature as well.)
Or give up technology and feel. If you’re below your vital power, “it’s going to be challenging, but you’ll feel in control,” says Gifford. Above your vital force, “your breathing and heart rate will continue to climb until you fail in about 2 to 15 minutes, depending on how high up you are.”
Still, you don’t need to know your vital strength to start exercising, notes Collins.
“The beauty of exercise is that it’s such a powerful drug that you can see the benefits without having to fixate on the workout as such,” he says. “I would hate to be a deterrent to exercise. The important thing is to do something.”