Skip to content

Thermal strain and fluid balance during a 72-km military route march in a field setting.

PMID 34005849 (2022): fluid, sodium — Time to exhaustion, Performance in heat, Cramp risk (study note for endurance athletes).

Last updated/Feb 23, 2026, 11:13 PM

Study note • PMID 34005849

Thermal strain and fluid balance during a 72-km military route march in a field setting.

Singapore medical journal2022 • DOI 10.11622/smedj.2021053
Evidence C56/100
Action 2: Consider

Worth trying if it fits your goal and context.

ELI5

In plain language

INTRODUCTION: A physiological profiling study was conducted to evaluate thermal strain as well as fluid and electrolyte balances on heat-acclimatised men performing a 72-km route march in a field setting. (cohort study; n=28 participants).

The abstract suggests a trade-off or negative effect affecting Performance in heat. Treat this as a signal, not a guarantee; confirm methods and context in the full paper.

Takeaways

What the abstract suggests

  • Study question: INTRODUCTION: A physiological profiling study was conducted to evaluate thermal strain as well as fluid and electrolyte balances on heat-acclimatised men performing a 72-km route march in a field setting.
  • The abstract suggests a trade-off or negative effect affecting Performance in heat.
  • Population: n=28 participants.
  • Protocol cues (title/abstract): 26 hours • 72 km.

Protocol

Protocol (as reported)

  • Intervention/exposure: fluid, sodium.
  • Dose/time/duration cues in abstract/title: 26 hours • 72 km.
  • Outcomes: Time to exhaustion, Performance in heat, Cramp risk.
  • Replication note: abstracts often omit adherence and timing; confirm details before changing training or supplementation.

Fit

Who it helps, and who should skip it

Who it helps

  • Athletes similar to the study population (n=28 participants) working on hydration.
  • Athletes who can measure Time to exhaustion, Performance in heat, Cramp risk with a repeatable workout or time-trial effort.

Who should skip

  • If you have symptoms or conditions that make the intervention risky, get professional guidance.
  • If you’re near race day and can’t safely test, defer the experiment.

Methods

What the study actually did

  • Design: cohort study.
  • Population: n=28 participants.
  • Outcomes measured: Time to exhaustion, Performance in heat, Cramp risk.
  • Protocol cues mentioned: 26 hours • 72 km.
  • Source: PubMed PMID 34005849 (2022) — Singapore medical journal.

Results excerpt

What the abstract reports

Our study found low thermal strain heat-acclimatised individuals during a 72-km route march.

Note: excerpts are short; for full context, read the paper.

Limits

Limitations & bias

  • Abstract-only summaries can miss critical details (population, protocol, adherence, and context).
  • Single studies often don’t generalize to your event, history, and training load; treat results as a starting point.
  • If your context differs (elite vs recreational; cycling vs running), adjust expectations and be conservative.
  • This is performance information, not medical advice.

Coaching beta

Get a plan that adapts to your life.

Join the 26weeks.ai TestFlight beta for adaptive coaching, recovery-aware adjustments, and race-week reminders.

Keep going

Sources