Exercise and immunity: moderate helps, extreme hurts
Roger Seheult's J-curve and Huberman's cold, flu and immune episodes agree that regular moderate exercise strengthens immunity while very intense bouts can temporarily weaken it. It helps active people train smart during cold and flu season.
What is the J-curve of exercise and immunity? Show answer
It is the pattern in which moderate exercise lowers your risk of getting sick compared with doing nothing, while more and harder exercise pushes the risk back up.
What was the moderate exercise dose in the McMaster trial Dr. Roger Seheult describes? Show answer
Students raised their heart rate to about 140 beats per minute for about 20 minutes, three times a week, for 18 sessions over six weeks.
What happened to the students who did not exercise before exams? Show answer
Their depression scores rose sharply over six weeks, which Seheult says shows that stress over time increases depression.
How did the high-intensity group compare with the moderate group in that trial? Show answer
Their depression scores fell less, their self-reported stress did not improve and their interferon levels went up.
What exercise dose does Andrew Huberman say primes the innate immune system? Show answer
Sessions of 60 minutes or less at a hard but not all-out effort, which raise baseline innate immune activity for many hours, perhaps up to 24.
What does Huberman say happens to the immune system after a marathon? Show answer
T cell and natural killer cell function drop well below baseline while stress hormones and cytokines run very high, leaving people severely immune compromised.
Which three patterns did Huberman find before his own serious colds? Show answer
Two hard workouts in one day, hard workouts followed by cold exposure while traveling, and nights of two hours of sleep or less.
What should you do about training after a single bad night of sleep? Show answer
Go back to sleep if you can. If not, exercise early at 25 to 50% reduced intensity and duration, and never sacrifice sleep for exercise.
What does Huberman advise eating after a long fasted morning workout? Show answer
Complex carbohydrates such as rice, oatmeal or pasta and some fruit within about an hour, which he says can reduce inflammatory markers by about 30 to 40% compared with water alone.
What should you do if you feel run down with malaise or a throat tickle? Show answer
Skip the workout, go home, take a hot shower or bath and get into bed early. If you already have symptoms, do not exercise at all.
How do Seheult and Huberman differ on what makes exercise harmful? Show answer
Seheult's evidence points to intensity, with heart rates around 180. Huberman's points mostly to duration and accumulated load, such as marathons, very long sessions and two hard sessions in a day.
What limit does the article note about the evidence? Show answer
Neither source presents a trial that counted infections across exercise levels, so the curve rests on mechanism, markers and observation, and the numbers are guides, not universal cut-offs.