Train with CORE: Simple Heat Training for Cyclists

Once you have done a heat ramp test, identified your ideal temperature zones, and gained some heat awareness, you are ready to start heat training. Heat training is a simple technique that has been proven to boost VO2max, power at lactate threshold, and time trial performance by 5–8% in both hot and cool conditions. The physiological changes mostly involve creating more blood plasma and red blood cells, allowing greater delivery of oxygen to muscles. The gains from season-long heat training allow you to train at a higher intensity, which further boosts your race performance.

Basics of heat training

The article Heat Training for Sporting Performance gives details on heat training. But the basics involve doing 2–3 heat sessions per week, with each session having 45–75 minutes in your heat training zone. This amount of time accumulated in the heat training zone is known as thermal load, and it is easily tracked in the CORE mobile app.

Accumulating this amount of thermal load is easy with a typical cyclist’s training plan. The required thermal load should be reached each week. Missing 2–3 weeks of heat training will greatly diminish the extra blood plasma you have created.

Note that while some people will choose to do a heat training block (2–4 weeks of 6 days/week of heat training), to get their plasma gains immediately, most find it more convenient to accumulate those gains more gradually with something like the schedule below. If you do choose a heat training block, the below schedule can be used for season-long maintenance.

Sample heat training schedule








Recovery ride

VO2max intervals

Easy endurance ride
(45–75 minute heat session)

Threshold ride

Recovery ride
(45–75 minute heat session)

Tempo ride

Endurance ride (include
45–75 minute heat session)


Details of the heat sessions

Wednesday, easy endurance ride

This ride should be zone 1 or easy zone 2 (50–60% FTP) and can be done outdoors or on the indoor trainer. If outdoors during cooler weather, you may need to wear a number of extra layers to elevate your core temp into the heat training zone. If your ride isn’t long enough to give you 45–75 minutes in the heat training zone, sitting in a hot bath or sauna after you ride can extend your heat session and give you the total thermal load you desire.

Friday, recovery ride

A recovery ride (<55% FTP) is a great time to accumulate thermal load. On the indoor trainer, an extra layer of clothes or turning off a fan will help you reach your heat training zone. During an outdoor ride, a lot of extra clothes may be needed, depending on the air temperature and humidity. And remember, your heat session can be extended with a hot bath or sauna immediately after the ride.

Saturday, long ride

Even though your long ride duration might total 2–6 hours, be sure to accumulate no more than 75 minutes in the heat training zone. More than that may cause excess fatigue. This means you’ll need to add and subtract layers during the ride to regulate your core temp. Arm/leg warmers, a beanie, and a light jacket may be enough to get you into the heat training zone during mild weather. Colder outdoor temperatures will require more layers and more planning.

Heat training during high intensity?

High intensity cycling while in the heat training zone causes a lot of stress to the body and is best avoided. However, heat training could be done immediately following the intense portion of the workout. For example, you could keep your core temp below the heat training zone while riding 2 x 20:00 at FTP. Immediately after that, you could add clothing and continue riding in zone 2, raising your core temp into the heat training zone.

Tracking thermal load

The CORE mobile app makes it easy to track your thermal load. You can see how many heat training sessions you’ve done in a week or month, and also the cumulative time you’ve accumulated in that zone. Remember that athletes can also easily share their CORE mobile app data with their coach – it will be synced to the coach’s app as soon as the athlete uploads it to the CORE app (or if using a Garmin device, as soon as the workout syncs with the Garmin app).

Next steps

Once you’ve become accustomed to heat training, the next step in using CORE is learning how to pre-cool before a race or intense workout.