Should we be individualising ice baths? The influence of body size and immersion time

A research review from the Performance Digest

Francisco Tavares

By Dr. Francisco Tavares
August 7th, 2019 | 4 min read

Contents of Research Review

  1. Background & Objective
  2. What They Did
  3. What They Found
  4. Practical Takeaways
  5. Reviewer’s Comments
  6. About the Reviewer

Background & Objective

The goal of this study was to compare the effects of cold water immersion (CWI) in football linemen (i.e. small body surface area to mass ratio [BSA:BM]) and cross-country athletes (i.e. large body surface area to mass ratio [BSA:BM]) performed after a heating protocol.

What They Did

The athletes were exposed to a heating protocol that consisted on 10-minutes of sitting in a heating chamber at a temperature of ~39ºC and relative humidity of ~40ºC followed by 20-minutes of exercise until the core temperature (Tc) reach 39.5ºC or volitional exhaustion was achieved. After that, athletes were immersed in cold water tubs at a temperature of 10ºC until the Tc achieved 37.5ºC. Core temperature was measured every minute during the CWI and was obtained from a temperature sensor that was ingested by the athletes. The analysis was performed once the athletes’ had reached a Tc of 37.5ºC, which in this case, was after 7-minutes. Therefore, the first athlete was removed from the CWI tub after 7-minutes (e.g. achieved Tc of 37.5ºC after 7- minutes).

What They Found

Differences between the groups were found for the cooling time to achieve the Tc of 37.5ºC (target Tc / time) and slope of lines of the Tc / time. The football linemen (FB) required significantly more time to reduce Tc to 37.5ºC (~11 minutes) than the cross-country (CC) athletes (~8 minutes). As expected, the Tc / time was significantly lower in the FB (~0.156ºC per minute) in comparison to CC (~0.255ºC per minute). Strong correlations were found between the rate of cooling and body mass, total BSA, BSA/mass, lean body mass/mass and % of body fat.

Practical Takeaways

The main takeaway message from this study is that body composition affects the decrease in Tc when athletes are exposed to CWI. In particular higher measures of body mass, total BSA, BSA/ mass, lean body mass/mass and % of body fat are associated to a decrease in the of rate of cooling of Tc.

Another important finding from this study is that cooling rates vary considerable between subjects, reinforcing the need to monitor individual rectal temperature during CWI. Lastly, a CWI protocol of 11 minutes at the temperature of 10ºC seems to be ideal to large athletes such as football linemen or other athletes such as rugby first rows.

Reviewer’s Comments

The findings from this study demonstrate that decreases in Tc from CWI are highly correlated with different measures of body composition. Subjects with lower BSA:BM should be exposed to more severe cold protocols in comparison to smaller BSA:BM when reductions in the Tc are desirable.

While it can be difficult to have cold baths with different temperatures within the same environment, by increasing the duration of the protocol one can increase the intensity of the modality when individualisation is desirable. Given that strong correlations were observed between the rate of cooling and % of body fat, coaching staff can use % of body fat as a reference to individualise CWI interventions.

Although I have never used the BSA:BM to individualise CWI interventions, I have provided some individualisation based on two factors: 1) perceived effectiveness and belief in CWI as a recovery modality; and 2) the percentage of fat mass. In order to respond to these two factors, I use cold tubs at different intensities, categorising them as severe (~10ºC) or less severe (~15ºC) and use different immersion times (e.g. 8 or 10 minutes). With this I can have a combination of 4 different intensities:
Low: 8 minutes at 15ºC;
Moderate – Low: 10 minutes at 15ºC;
Moderate – High: 8 minutes at 10ºC
High: 10 minutes at 10ºC

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    Francisco Tavares

    Dr. Francisco Tavares

    Francisco is the Performance Coordinator for Sporting Lisbon and has previously worked as a S&C coach in elite rugby with the Chiefs Super Rugby franchise and the PRO14 team Glasgow Warriors. He holds a PhD from Waikato University and is a published author.

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