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Published Nov 2025
Goa, India · November 2025 · IRONMAN 70.3

IRONMAN Goa 2025: GEL100 hydration protocol across 30 athletes

GEL100 fuelling protocol tested across 30 athletes in 34°C coastal heat. Pre-race loading, on-course dosing, electrolyte replacement, and post-race outcome data. The methodology and the honest findings — including what did not go to plan.
30
Athletes
34°C
Race temp
87%
GI tolerance
28/30
Finished
IRONMAN Goa 2025: GEL100 hydration protocol across 30 athletes
Field team
Amit Dahanukar · Ameya Kale · 4 nutrition volunteers
01

Background & Objectives

IRONMAN 70.3 Goa presented an atypical testing environment for GEL100: 34°C ambient temperature, 78% humidity, a 90km bike course with 1,200m elevation gain, and a run leg fully exposed to direct sun from 08:30. These conditions create significantly elevated sweat rates, accelerated glycogen depletion, and increased GI stress risk — exactly the conditions under which a 2:1 glucose-fructose formulation needs to hold up.

Our objectives: document each athlete's fuelling protocol, record GI incidents in real time, and collect finish-line self-reported data on energy, cramping, and tolerance. This is field observation — not a controlled trial. We document it exactly that way.

"We were not running a controlled trial. This is field observation, not RCT data. We document it that way — and we publish the parts that did not go to plan."

02

Protocol

Athletes were briefed individually the evening before the race. We did not prescribe a single fixed protocol — we worked with each athlete's existing fuelling plan and adapted GEL100 into it based on their anticipated bike split, historical GI sensitivity, and heat acclimatisation. This created variance, which we documented.

Phase
Protocol
Field notes
Pre-race
1 GEL100 + 500ml water, 45 min before swim start
22 of 30 followed this. 8 preferred no pre-race gel.
Bike — early
1 GEL100 every 30 min from km 15, with 250ml water
Standard 2:1 fructose-glucose at ~60g CHO/hr
Bike — late
Reduce to every 40 min if GI discomfort noted
4 athletes reduced cadence. All recovered by T2.
Run
1 GEL100 at km 3 and km 9, water at every aid station
Heat reduced appetite in 11 athletes. Gel adherence dropped.

The biggest protocol deviation was on the run: 11 athletes reported reduced appetite in the heat and skipped one or both run gels. Of these, 7 reported energy fade in the final 5km — consistent with published literature on heat-induced appetite suppression and late-race glycogen depletion in 70.3 events.

03

Findings

GI Tolerance
26 / 30

No GI issues across the full race. 4 reported mild nausea on the run — all 4 had not paired GEL100 with the recommended 250ml water.

Energy at Finish
7.4 / 10

Mean self-reported energy at finish line, collected within 10 min. Range 5–9. Athletes who skipped run gels averaged 6.1.

Cramping
3 / 30

Significant cramping requiring a stop. All three had consumed fewer than 3 of 4 recommended run electrolyte drinks.

Finish Rate
28 / 30

2 DNFs — one bike mechanical, one heat illness unrelated to fuelling. Zero nutrition-related DNFs.

04

What Didn't Work

We document this section in every field report. It is not an afterthought.

Run gel adherence
Heat-induced appetite suppression caused 11 athletes to skip one or both run gels. Future briefings will address this explicitly — appetite is not a reliable hunger signal in extreme heat.
Water pairing
All 4 GI incidents involved athletes who did not pair GEL100 with adequate water. The 250ml recommendation was briefed verbally but absent from the written protocol card. Corrected for future events.
Pre-race data gap
We did not collect pre-race carbohydrate loading data — meaning we cannot assess whether athletes who skipped the pre-race gel had higher glycogen from better loading. A methodological gap we will close at future events.
05

Formulation Notes from the Field

Three observations passed to our formulation team after this event:

1.
Texture in heat

GEL100 became thinner at 34°C — rated as positive by several athletes. No flavour degradation. Expected behaviour. No action required.

2.
Electrolytes above 32°C

3 cramping incidents raise a question about whether GEL100's 365mg electrolyte profile is sufficient as standalone electrolytes above 32°C. Current assessment: the issue was water intake, not electrolyte dose. Monitoring at future events.

3.
Late-race sweetness fatigue

4 athletes independently requested a less sweet option for the run. Known phenomenon in long-course racing. Passed to formulation team as a product development consideration.

06

Conclusions

GEL100 performed well under high-heat conditions when the protocol was followed correctly. The 87% GI tolerance rate is consistent with published figures for 2:1 glucose-fructose formulations. The 4 GI incidents were attributable to water pairing non-compliance, not formulation issues.

The more significant finding is the run gel adherence drop in heat — a behavioural and briefing problem, not a product one. Pre-race protocol cards have been updated accordingly.

Next field report: Malnad Ultra 2025 — collagen and iron supplementation across a 20-week training block leading into a 60km trail race in the Western Ghats.