Endurance capacity impairment in cold air ranging from skin cooling to mild hypothermia
Two pages on PainSci cite Wallace 2024: 1. Whole Body Cryotherapy for Pain 2. It’s surprisingly hard to recover from being really chilly
PainSci commentary on Wallace 2024: ?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided wherever possible.
I bet I haven’t let my core temperature drop more than fraction of a degree in twenty years. That is, cold enough to really get shivering — mild hypothermia. I hate that state, and I’m pretty good at avoiding it!
And apparently it’s amazingly hard to recover from. I absolutely would have assumed that hard exercise would nuke mild hypothermia, within a matter of minutes. As Alex Hutchinson explains, this new evidence from Wallace et al says nope: even slightly reduced core body temp is incredibly persistent: “even cycling to exhaustion isn’t enough to warm you up if you’ve lingered for long enough in temperatures around the freezing mark.”
And I am very impressed by how little effect hard exercise had on those low core body temperatures. Definitely a surprising result.
The other noteworthy result here: endurance performance was strongly impaired by being chilled, even if it’s just superficial (rather than a drop in core body temperature). While athletes were able to warm up from superficial chilling much quicker, their performance was greatly reduced.
original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.
We tested the effects of cold air (0°C) exposure on endurance capacity to different levels of cold strain ranging from skin cooling to core cooling of Δ-1.0°C. Ten males completed a randomized, crossover, control study consisting of a cycling time to exhaustion (TTE) at 70% of their peak power output following: 1) 30-min of exposure to 22°C thermoneutral air (TN), 2) 30-min exposure to 0°C air leading to a cold shell (CS), 3) 0°C air exposure causing mild hypothermia of -0.5°C from baseline rectal temperature (HYPO-0.5°C), and 4) 0°C air exposure causing mild hypothermia of -1.0°C from baseline rectal temperature (HYPO-1.0°C). The latter three conditions tested TTE in 0°C air. Core temperature and seven-site mean skin temperature at the start of the TTE were: TN (37.0±0.2°C, 31.2±0.8°C), CS (37.1±0.3°C, 25.5±1.4°C), HYPO-0.5°C (36.6±0.4°C, 22.3±2.2°C), HYPO-1.0°C (36.4±0.5°C, 21.4±2.7°C). There was a significant condition effect (P ≤ 0.001) for TTE, which from TN (23.75±13.75 min) to CS (16.22±10.30 min, Δ-30.9±21.5%, P = 0.055), HYPO-0.5°C (8.50±5.23 min, Δ-61.4±19.7%, P ≤ 0.001), and HYPO-1.0°C (6.50±5.60 min, Δ-71.6±16.4%, P ≤ 0.001). Furthermore, participants had a greater endurance capacity in CS compared with HYPO-0.5°C (P = 0.046), and HYPO-1.0°C (P = 0.007), with no differences between HYPO-0.5°C and HYPO-1.0°C (P = 1.00). Endurance capacity impairment at 70% peak power output occurs early in cold exposure with skin cooling, with significantly larger impairments with mild hypothermia up to Δ-1.0°C.NEW & NOTEWORTHY We developed a novel protocol that cooled skin temperature, or skin plus core temperature (Δ-0.5°C or Δ-1.0°C), to determine a dose-response of cold exposure on endurance capacity at 70% peak power output. Skin cooling significantly impaired exercise tolerance time by ∼31%, whereas core cooling led to a further reduction of 30%-40% with no difference between Δ-0.5°C and Δ-1.0°C. Overall, simply cooling the skin impaired endurance capacity, but this impairment is further magnified by core cooling.
This page is part of the PainScience BIBLIOGRAPHY, which contains plain language summaries of thousands of scientific papers & others sources. It’s like a highly specialized blog. A few highlights:
- Topical glyceryl trinitrate (GTN) and eccentric exercises in the treatment of mid-portion achilles tendinopathy (the NEAT trial): a randomised double-blind placebo-controlled trial. Kirwan 2024 Br J Sports Med.
- Placebo analgesia in physical and psychological interventions: Systematic review and meta-analysis of three-armed trials. Hohenschurz-Schmidt 2024 Eur J Pain.
- Recovery trajectories in common musculoskeletal complaints by diagnosis contra prognostic phenotypes. Aasdahl 2021 BMC Musculoskelet Disord.
- Cannabidiol (CBD) products for pain: ineffective, expensive, and with potential harms. Moore 2023 J Pain.
- Moderators of the effect of therapeutic exercise for knee and hip osteoarthritis: a systematic review and individual participant data meta-analysis. Holden 2023 The Lancet Rheumatology.