Train with CORE - Precooling

Once you’ve developed heat awareness and have become accustomed to heat training, it’s time to focus on cooling measures. Even though precise, systematic heat training will improve your body’s ability to cool itself, there are still additional measures you can take.

The benefits of pre-cooling before a race or challenging workout are well understood by many coaches and are well documented by sports scientists. The physics are simple – lowering your core temp before you start exercising delays the inevitable performance loss caused by elevated core temps.

Cold baths and ice vests are sometimes used for pre-cooling. But many athletes find that a simple ice slushie is the easiest way to pre-cool. Below, we’ll describe how it’s done and give a simple workout to find out your optimal slushie intake.

Ice slushie recipe

Sure, making an ice slushie is simple – just add ice and water to a blender. But have you considered how much to drink, and when? The quantity is a pretty simple formula. While researchers have used various volumes, 8g of slushie per kg of body weight is a good starting point for your recipe. To make blending easier, use ¾ of that weight in ice and ¼ of the weight in water.

Sample slushie quantities, metric

For those using imperial measurements, the total volume is 0.12 ounces per pound of body weight. For ease of blending, one quarter of that should be water, and the rest ice.

Sample slushie quantities, imperial

When to drink the slushie

Drinking a little of the slushie at a time seems to work better than drinking it all at once. Try spreading it out over 15–30 minutes. If on the bike, this could be done during your warmup.

Optimizing your slushie

Before trying a pre-race slushie, you’ll want to practice drinking your slushie during training. If you also monitor your core temp, power/pace and heart rate, you can optimize the slushie quantity and timing. This will also help train your digestive system to handle so much cold fluid.

Workout 1

Do a baseline test, with no slushie. Preferably this is done indoors so you can replicate environmental conditions each week. During the workout, try to hold your power/pace steady and monitor your core temp and heart rate. Note your perceived effort.

• 15:00–30:00 warmup at an easy pace.
• 2 x 20:00 at FTP on the bike (or at tempo pace on the treadmill), 10:00 easy between each.
• 15:00 cooldown.

Workout 2

The next week, repeat Workout 1, but drink a slushie during the warmup. Keep the same power/pace as the first week, monitor your core temp and heart rate, and note your perceived effort. Also note if you have digestive issues. After the workout, analysing the workouts on training software will let you easier visualise the differences between the two workouts.

Workout 3

Repeat Workout 2, but vary the quantity or timing of the slushie. If you had stomach troubles, try reducing the quantity or spreading out its consumption over a longer time. If you had no problems with digestion, try a slushie 20% larger an see if you get additional benefits without stomach issues.

Next steps

Once you’ve optimized your pre-cooling slushie strategy, you can focus on per-cooling – cooling during a workout or race. The slushie will delay your heating by 45–60 minutes. So for workouts/races longer than that, you’ll need additional strategies to stay cool.