Heat Wave Survival

Posted on 10 Jun 2016 08:36:13 Posted By Tim Lawson

Heat Wave Survival

Even the best can get caught out, when a little forethought and preparation can prevent unnecessary sun related injury.  Who can forget the severe sunburn suffered by Chris Froome in 2014.  Checkout the Cycling Weekly report here.

Let’s not forget that sunburn is an avoidable injury

Most people are aware of the potential chronic health risks from sunburn, but it is also worth considering that sunburn is an inflammatory condition placing additional stress on the body.  This additional stress will compromise the body’s ability to adapt to training.

Prevention really is the best option. 

Whilst many options have been used to treat sunburn, researchers warn that there is no way to reverse damage to epidermal cells – (Han and Maibach, 2004)2.  In their 2004 review of treatment options Han and Maibach reported that the most effective practical approach to sunburn was to treat the pain, redness and swelling with emollient creams (in an emergency the coconut oil based Secret Training anti chaffing cream seems to work pretty well!) and anti inflammatory pain killers.

Recent reports in the press have highlighted a WHICH survey (Fletcher, 2016)3 suggesting many once a day sunscreens lose up to 74% of their effectiveness after 6-8 hours.  Clearly this is still significantly more protection that if no sunscreen was applied at all and obviously it is not always practical to stop in the middle of an event to reapply sunscreen!  However, a quick stop during training may be worth considering for those long training days, especially when its tempting to chat at the coffee stop for a little longer than usual.

Some practitioners have questioned the use of sunscreen and other topical creams for use during exercise hypothesizing that they may reduce evaporative cooling via sweat.  Some support for this stand can be found in a 1984 study which showed that sun screen usage resulted in a higher mean skin temperature, than in a no sun screen condition, in a short exercise test (Wells, Jessup, & Langlotz, 1984)4. Higher skin surface temperatures reduce the temperature gradient between the core temperature and the surface of the skin and may therefore compromise thermoregulation. 

In a more recent study however, Connolly and Wilcox (2000)5 demonstrated that the use of sunscreen resulted in a cooler skin temperature, thus increasing the potential for heat loss. Although offering a robust defense of their methodology, which they believe to be superior to the earlier study, they were unable to offer a definitive explanation as to their findings.  Interestingly they did note that the amphipathic nature of sun screens (contains molecules with water-loving and fat-loving properties) may result in more water being trapped on the skin and available for evaporative cooling, rather than just dripping off the skin without contributing to cooling.

A similar Australian study was conducted to clarify whether wearing sunscreen could compromise the ability to maintain core temperature in safe limits during exercise.  Naughton et al. (2000)6 concluded that there were no detrimental effects to exercise performance or thermoregulation through sun screen usage.

In conclusion, whilst there is limited published research on the effects on sunscreen on sports performance, there is little doubt that sunburn should be avoided.  Some sun exposure is beneficial for natural vitamin D production but this is best done with controlled exposure – there is little support for forgoing sun screens for sports performance.

HYDRATION is the other main consideration when the temperature rises.

WE tend to be more alert to hydration during exercise but it is worth remembering that more fluids may be required during the day.  Under normal conditions you may be able to complete your evening workout or race with minimum extra fluids.  When its hot if extra care has not been taken during the day hydration requirements will be increased not only because of conditions during exercise but because exercise has begun in a more dehydrated state!

Practical Tip

When the weather is really hot try making your energy/hydration drink up the night before and storing in the freezer over night.  Whilst you may have to wait a little while for your first drink this should ensure a good supply cool drink for several hours.  This is also a good way of keeping drinks cooler for longer when stored in a thermal cool box or bag.

 

References

  1. Miners, A. L. (2010). The diagnosis and emergency care of heat related illness and sunburn in athletes: A retrospective case series. The Journal of the Canadian Chiropractic Association, 54(2), 107–117. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2875908/

  2. Han, A. & Maibach, H. (2004). Management of Acute Sunburn. American Journal Of Clinical Dermatology, 5(1), 39-47. http://dx.doi.org/10.2165/00128071-200405010-00006
     
  3. Fletcher, Y. (2016). Once a day sun creams - Which?. Which.co.uk. Retrieved 9 June 2016, from https://www.which.co.uk/reviews/sun-creams/article/once-a-day-sun-creams
     
  4. Wells, T., Jessup, G., & Langlotz, K. (1984). Effects of Sunscreen Use During Exercise in the Heat. The Physician And Sportsmedicine, 12(6), 132-142. http://dx.doi.org/10.1080/00913847.1984.11701879

  5. Connolly, D. A. J., & Wilcox, A. R. (2000). The efforts of an application of sun cream on selected physiological variables during exercise in the heat. Journal of Sports Medicine and Physical Fitness, 40(1), 35-40. http://www.minervamedica.it/en/journals/sports-med-physical-fitness/article.php?cod=R40Y2000N01A0035
     
  6. Naughton, G and Carlson, John and Gibbs, M and Snow, R (2000)  The effects of wearing sunscreen lotion on thermoregulatory responses during exercise in the heat in adult and adolescent males. In: Proceedings of the International Conference on Physiological and Cognitive Performance in Extreme Environments. Defence Science and Technology, Department of Defence , Canberra, ACT, pp. 72-75.
     
  7. [PDF] EFFECTS OF WEARING SUNSCREEN LOTION ON THERMOREGULATORY RESPONSES DURING EXERCISE IN THE HEAT IN ADULT AND ADOLESCENT
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