217 ‒ Exercise, VO2 max, and longevity | Mike Joyner, M.D.

KEYPOINTS

• 01

  The roughly 50% mortality benefit of activity has held up for 70 years.

  Joyner, a Mayo Clinic anesthesiologist and exercise physiologist, begins with post-war London. Bus conductors climbing the stairs all day had far less cardiovascular disease than the seated drivers, and active and sedentary telephone workers showed similar gaps. He calls the roughly 50% risk reduction 'incredibly consistent' across later studies, including Harvard alumni and Swedish finishers of the 90-km Vasaloppet ski race compared with matched controls. NCI data showed about four to six extra years of life expectancy with substantial activity.

• 02

  More fitness keeps helping, with no clear plateau.

  Peak capacity is measured in METs; one MET is about 3.5 mL O2/kg/min, and running a 10-minute mile is about 10 METs. Researchers once thought the benefit plateaued at 10–12 METs. A Henry Ford group in Detroit found it keeps rising to 15–16. In the study Attia highlights, the bottom 25% for VO2 max had a hazard ratio of about 5.04 versus the top 2.5%, and the third quartile was still at about 2.75. Joyner once suggested that, apart from cancer screening, people reaching 12–14 METs might safely ignore much else.

• 03

  Joyner sees no meaningful J-curve, though lifelong hard training may raise AFib risk.

  He calls the real-world Vasaloppet data dispositive. Lifelong heavy trainers seem to have more atrial fibrillation than healthy people active at about 50–70 MET-hours a week. But they show no excess of fatal ventricular arrhythmias, their AFib risk is probably still lower than that of sedentary, hypertensive, obese or diabetic people, and AFib is treatable. The biggest gain comes from the first 10–15 minutes a day of activity, which improves muscle insulin sensitivity and buffers against weight gain.

• 04

  Inactivity is devastating, and decline with age is steep.

  In 1966 NASA had five college-age men spend three weeks on bed rest at UT Southwestern, prompted by astronauts returning atrophied. Thirty years later Ben Levine and the late Jere Mitchell re-tested them: three weeks of bed rest had caused losses comparable to 30 years of aging. Joyner says around the mid-70s the limit shifts from heart and lungs to muscle strength. He cites the claim that about 70% of 70-year-olds can't get up off the floor.

• 05

  Build a high VO2 max early, because you lose about 10% per decade.

  VO2 max typically falls about 10% per decade (estimates range from 9% to 12%). Trained people may hold steady until their late 30s or early 40s. An elite group retested in their late 40s and 50s showed that the third who kept training hard had minimal losses. Starting from 60 rather than 35 mL/kg/min means that at 60 or 70 you can out-perform an untrained 30-year-old. Attia's 'Centenarian Olympics' asks you to reverse-engineer what you want to do at 85.

• 06

  Fitness improves the autonomic nervous system, measurable by heart-rate recovery.

  Fast heart-rate recovery after a maximal test reflects strong vagal tone. The vagus nerve also drives heart-rate variability and suppresses abnormal beats. Blood pressure normally rises sharply during a VO2 max test, from about 115/75 to 160/95 or more. Cardiac output (heart rate × stroke volume) can climb from about 5 to 15–20 L/min, and 30–40 L/min in elite athletes. Joyner suggests worrying less about HRV and more about whether you're doing 30, 60, 100 or 180 minutes a week.

• 07

  Elite endurance training has converged on a mostly easy, some hard model.

  Across running, cycling and swimming, roughly 60–70% of training is easy to moderate, 20–30% is harder and about 10% is very hard. Joyner says Kipchoge likely runs 14–18 hours a week at 7,000–8,000 ft, with perhaps 10 miles a week faster than race pace. Joyner notes the top performers of the late 1960s and early 1970s had VO2 max values in the high 70s, not 90. Since then the gains have come mainly from better races and longer careers.

• 08

  You can out-exercise a bad diet only up to a point.

  Lumberjacks ate 5,000–6,000 calories a day and the Old Order Amish stay lean through manual labor. Joyner says that in a modern high-calorie, low-activity world that's the caveat. Body temperature rises only a degree or two even as metabolism climbs 10–20-fold, an example of homeostasis.