Pablo Marcos is a professional performance coach, sports scientist, and CORE Coach who went 9:32:52 at the Hawaii Ironman World Championships. Here, he discusses his use of CORE both in training and in racing.

CORE for heat training and acclimation

I used CORE not only in training for Kona but as a tool to improve performance overall. I used heat training protocols to enhance my haematological parameters at different times of the year (timed with our season plan), and then used it for specific heat acclimation for events such as St George and Kona.

For heat training, I used the protocols described on the CORE website, testing different “ways” (extra clothing, no fan, heated tent, etc). These are part of my research for the MSc Thesis. I found there is no significant difference between them as long as the heat training zone is reached. What I did find is that some of my athletes using CORE to prepare for Kona responded differently to different strategies for heat training and to reach their heat training zones. 

Heat acclimation in my case was done mostly on the turbo trainer with a tent controlling the temperature and humidity conditions. When outdoors, I trained with extra clothing and “low breathable” clothing to accumulate humidity close to my body. In the tent we increased temperature first and then added humidity after. However, we never reached Kona conditions, as I reached heat training zones prior to those temperatures. I complemented high intensity and specific sessions with easier aerobic sessions that I would follow with a hot bath or sauna.

CORE for pacing an cooling during the race

During the race, I used CORE for heat pacing, knowing when to cool, and general monitoring. Having the knowledge of my heat threshold and zones from nearly two years of using CORE makes it quite simple to anticipate and act accordingly before temperature raise even happens. Having done St. George earlier in the year and a couple of other events aiming at replicating conditions, I was prepared and knew how my core temperature changed.

For example, after the swim, my temperature was over the sky (something I also understand is due to an offset issue with the CORE sensor during swimming). However, this also meant my main priority on the first quarter of the bike is to cool down even when the external temperature was nice and not hot at all.

From there it was more a matter of knowing the course, anticipating where intensity will increase (and hence internal temperature), and staying on top of hydration and cooling products. On the marathon I had a target pace but this was adjusted a lot by monitoring my internal temperature. Thus, I noticed on any long incline I had to significantly drop the pace to avoid core temp rising. I made a big mistake after the energy lab as the excitement of the home stretch in the Queen K made me underestimate the long gradual inclines and the spacing between aid stations. At this point my CORE Body temp rose to 40.2° C (104.4°F).

I am overall really pleased with my race. It is indeed true that I didn’t succeed in controlling my core body temperature on the last third of the event due to my own mistakes and miscounting the amount of aid stations I was going to go through to cool down. But overall, I felt in control the entire day and stuck to my numbers and what I knew I was capable of.

Simulating Kona in the UK

Preparing with CORE allowed me to improve haematological values through heat training throughout the entire season and that is something that I do believe made me a better athlete in general. But obviously, when preparing for the heat and humidity of Kona, all the specific sessions controlled by CORE were key. I live in a place (Britain) where 25° C (77° F) is considered a high temperature and we are famous for the opposite type of weather from Kona. We are not able to train in similar conditions even during the summer, so CORE let me simulate those conditions.