Updated: Nov 14, 2022
Longer days, less layers and clear skies; summer is for the most part, a great time of year to be a runner. Despite this, running in the warmer months can bring a new set of challenges when it comes to lacing up and heading out the door.
In a very brief sense, your body is forced to deal with heat in two ways:
When the ambient temperature rises (how hot and / or humid the conditions are that you're running in).
When your core temperature rises. This is driven by how hard you're working, hormones, lifestyle factors and the ambient temperature.
As your core temperature rises, your body's process of thermoregulation works to maintain homeostasis with two mechanisms.
The first is sweating, which cools your skin as it evaporates. The rate of evaporation is inversely related to the relative humidity. The higher the relative humidity, the lower the rate of evaporation. At 100% humidity, heat is gained via condensation on the skin as fast as heat is lost via sweating.
The second is vasodilatation, where the blood vessels under your skin get wider and blood flow to the skin is increased and directed away from the warmer parts of your core. This allows your body to release heat through radiation. Further, women can experience an elevated basal body temperature in weeks 3 - 4 (the postovulatory phase) of their menstrual cycle. This could also mean an increased metabolic rate meaning that you'll need to ensure you're fuelling and hydrating adequately. It could also mean that you find yourself sweating more than you usually would.
There are a number of things we can do, both preventive and in response, to mitigate the negative component of running in the heat. Those strategies include:
Ensuring that you are pre-cooling by staying in a cool environment for as long as possible before starting your run (that includes sleeping in a cool environment).
Wearing appropriate clothing (i.e. sun sleeves, light coloured and lightweight clothing, a hat).
Taking on fluid and any necessary electrolytes. As you start to inevitably sweat more, you will lose fluids, vitamins and minerals. Even a small change in the balance of your hydration and electrolytes may cause a performance decrease so ensure that you are well hydrated prior to running, as well as drinking throughout your run.
Start your run early or late to avoid the heat of the day.
Be aware that you are likely to run slower than you usually might. The heat will boost your heart rate regardless of what pace you are running but the fitter you are, the better your body will cope with the heat.
Your perception of heat will change over the course of the warmer months so try to embrace it for the performance benefiting factor it is.
If you're training for a race and the conditions are likely to be on the warmer side, the period for adaptation to the heat is in the vicinity of 14 - 21 days. The recommendation is exposing yourself to heat similar to conditions you're likely to experience through shorter easy runs in the first instance and building towards longer and more intensive runs the closer you get to your event date.
So you've finished your run and you've worked up a sufficient sweat; what can be done now to maximise recovery before your next run?
Aim to take on hydration immediately after finishing.
Get cool once you've finished your run - either by soaking in some cool water or heading into the air-conditioning.
Try to lower your core body temperature by having a frozen drink.
Training in the heat requires a healthy respect for the extra strain it can take both on training and recovery but it is also a great opportunity to use a training stimulus that is actively available to everyone in order to push adaptations that you may not ordinarily be able to attain.