US EditionWhat’s the cap on human energy expenditure? Elite athletes reveal ‘metabolic ceiling’
A study tracking 14 elite ultra-endurance athletes found their long-term energy burn maxes at about 2.5 times basal metabolic rate despite short bursts up to 7 times, researchers said.
- On October 20, a study published in Current Biology reports even elite ultra-runners, cyclists and triathletes hit a metabolic ceiling that cannot be surpassed over prolonged periods.
- To test the 2.5-times hypothesis, the researchers recruited a group of elite endurance athletes expected to challenge the proposed metabolic ceiling of 2.5 times BMR.
- The researchers recruited 14 ultra-runners, cyclists and triathletes and followed them for a 52-week tracking period while tracing doubly labeled water with deuterium and oxygen-18 in urine isotope measurements to estimate CO2 output and calories burned.
- Short-Term race data show athletes briefly burned six to seven times their BMR—about 7,000 to 9,000 calories per day—without sustained long-term exceedance.
- Researchers found athletes compensated by reducing other energy use, warning that sustaining excess burn risks tissue breakdown and noting the small sample may miss outliers; future research should identify mechanisms.
12 Articles
12 Articles
Ultra-permanent athletes perform maximum physical performance, but their energy also has a biological limit. Researchers now find that the calorie consumption of athletes does not exceed 2.5 times the basic turnover in the long term. The results shed a new light on the resilience of the human body.
der Standard AT
der Standard DEExpensive measurements on 14 ultra-runners and triathletes showed that they too can consume hardly more than 2.5 times their basic turnover of energy in the long run
Ultra-endurance athletes push metabolic limits of the body
Study participant Joe McConaughey en route to a speed record on the Arizona Trail in 2021. Credit: Michael Dillon (CC BY-SA) Researchers have found that no matter how much strength and grit the most intense ultra-athletes have, they ultimately cannot exceed the human body’s ‘metabolic ceiling’ over a long period. The metabolic ceiling refers to the maximum number of calories a body can burn at one time. Previous research has suggested that peop…
Ultra-endurance athletes can burn up to 8,000 calories per day
It’s hard not to admire marathon and ultra-runners for their physical stamina and prowess. They’re not only inspirational, but are also testing the limits of human biology with their mental grit and muscle strength by logging hundreds of miles and days at a time. According to a study published today in the journal Current Biology, even the most extreme endurance athletes cannot surpass a certain level of calorie burning. What is the metabolic ce…
Ultra-endurance athletes test the metabolic limits of the human body
When ultra-runners lace up for races that stretch hundreds of miles and days, they're not merely testing their mental grit and muscle strength—they're probing the limits of human biology. Reporting in Current Biology, researchers found that even the most extreme athletes cannot surpass an average "metabolic ceiling" of 2.5 times their basal metabolic rate (BMR) in energy expenditure.
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