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Participant Information: Running in Hot Weather Advisory

When temperatures are high on race day, here are some tips to stay cool and stay safe

The B.A.A. and the B.A.A. Half Marathon Medical Team urge all runners to consult their personal physicians prior to training and running the marathon. Traditionally, distance running is a safe and healthy form of exercise, but there are inherent risks associated with running extreme distances, especially if you have certain pre-existing medical conditions, or if there are race-day temperatures. Only a physician familiar with your personal medical history, current health status, medications, and your pre-existing risk factors can advise you as to whether you are fit to run the B.A.A. Half Marathon. Taking these simple steps (and heeding the advice of your personal physician) will give you the ability to make the right decisions and enjoy a healthy race.



Of all the adversities that runners and half marathoners face, heat is the number one offender. This is because it can bring on two conditions that can negatively affect your performance… overheating and dehydration. At times, the unpredictable nature of Boston’s weather, especially in October, can offer warmer than normal temperatures, placing runners at risk for the potential of exercise induced heat illness.  The degree of risk is determined by two key factors, heat and humidity. Simply stated, when both factors are present runners are encouraged to slow down from their normal pace. If you are experiencing an illness (fever) or cold, your risk factors will increase. Deciding not to run when temperature extremes are present or stopping if heat illness becomes an issue, is vital to your safety. Failure to do so can result in a rapid rise in temperature to dangerous levels, which may damage the heat regulatory mechanism in the brain. The symptoms of impending heat illness include weakness, heat sensation on the upper body, a feeling of being light headed, confusion, blurred vision, shortness of breath, nausea, vomiting, a generalized sensation of tingling in the neck and shoulders which can progress to disorientation, profound weakness, and collapse.

1. Public address announcements stating the risk of heat illness or hypothermia will be made in the pre-race area. Be aware that extreme weather changes may occur after the start of the race.

2. Fluids are available before, during, and after the race. The medical team suggests you drink a pint of fluid two hours before the start and then take fluids along the course at regular intervals and as needed based on personal experience. Note: medical problems can arise from excessive (hyponatremia), as well as insufficient, intake of fluids. Both water and Gatorade Endurance Formula will be available at each aid station along the route. Gatorade Endurance Formula is a specialized sports drink that contains approximately twice the amount of sodium (200 mg per 8 ounces) of Gatorade Thirst Quencher, along with chloride, potassium, magnesium and calcium to help sustain hydration by better replacing what is lost in sweat. For more information on hydration, go to or Gatorade Endurance Formula will help replace some of these minerals lost during exercise, but will not prevent hyponatremia. If you feel ill along the course, we strongly recommend that you seek medical attention at one of the first aid stations.

3. Several First Aid Stations are located along the route and mobile emergency vehicles are positioned for transport to major medical centers. Teams of medical personnel are located at the finish line to assist participants in need of attention, and these teams are supported by a larger medical station located just past the finish line in White Stadium

4. If you are feeling ill and experiencing medical problems, you are strongly urged to withdraw from the race. Local EMS, and buses staffed with medical personnel will pick you up at any of our First Aid Stations or along the route. Participants will be transported to the Finish Area at the rear of the primary medical tent. In some cases you may be transported to a local hospital for follow-up care. We ask that you have hospital EMS contact us once you arrive.



The B.A.A. and the B.A.A. Half Marathon Medical Team remind runners to be aware of the many risks involved in running a half marathon. It must also be understood that a runner’s susceptibility to a particular risk will depend on a number of different factors, including factors unique to the individual runner. Medical knowledge and medical therapies relating to distance running are continuing to evolve and develop. For instance, one of the risks which is receiving attention is hyponatremia, and there are studies which indicate that females, runners with a slight build, runners that take over four hours to complete the course, and those taking nonsteroidal anti-inflammatory drugs (such as Advil, Motrin, Aleve, ibuprofen, naproxen, etc.) may be particularly susceptible to this risk. This is usually associated with weight gain.

One suggestion for the runner is to measure their weight before and after a training run. One should finish a long run at about the same weight or up to 2% below the pre run weight. Changes above or below these levels may be predisposed to hyponatremia or hyperthermia respectively. It’s your responsibility to understand your specific fluid needs and not over drink before, during, or after the event. Unfortunately, no one study is definitive or comprehensive. Therefore, the B.A.A. and the B.A.A. Half Marathon Medical Team urge all participants to read publicly available materials and to educate themselves fully about the medical risks associated with running a marathon.

It’s very important for the runner to determine hydration needs prior to the race. However as a rough guide, if you’re a fast runner on a pace of less than 1 ½ hours, drinking about 16 oz per hour is usually adequate. If you’re on a pace to finish in more than 2 ½ hours, about 8 oz per hour is usually adequate. There are frequent water/Gatorade stations along the course for your convenience. However, it’s not necessary to stop at every station. This could result in over-hydration. It is also very important to not over-hydrate at the end of the race. Rehydration should be gradual over the next 24 hours. Two ways to continually monitor your fluid status in training are to measure your weight, stripped down, before and after a run. You should gain no weight and typically lose up to 2% of body weight. After determining your fluid needs, stick to this plan during the race. The second is to make sure your urine stays yellow, not clear (overhydration) and not dark like apple juice (dehydrated), both are key indicators when determining your hydration status.

B.A.A. Moment

Running in Hot Weather Advisory

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