When used correctly, heart rate data can be a useful and powerful tool to track and improve your training. And never is that more relevant than during the sizzling summer months.
Summer training adds an extra layer of difficulty to running thanks to the sweltering heat. And it’s not just the higher temps, but the humidity too. Combined, these can make running outdoors a real challenge, particularly when you want to run long, hard or fast.
Enter heart rate training. Knowing your heart rate at any given time provides valuable information regarding how hard you’re working. Even if you aren’t moving quite as fast as you think you should (or want to be), you could still be working just as hard to sustain a similar effort.
Getting access to your heart rate data has never been easier. Many newer versions of popular GPS watches and fitness tracking devices now have built-in heart rate monitors that can track your heart rate 24/7 using wrist-based technology. Traditional heart rate monitors that utilize a chest strap are also as popular as ever and provide the most accurate data.
Just as your heart rate will vary based on the time of day, your level of fatigue and even how well you’re hydrated, working out in the heat is going to feel much harder and thus affect your heart rate. So rather than push yourself to hit or maintain certain paces (that you would expect in cool/ideal conditions), aim instead to hit a target heart rate.
Heart rate zones are a common way to categorize how hard you’re working. While individual numbers vary, the following zones provide a general overview for determining how hard you should be running:
Zone 1: Active Recovery – 50-60% HR max
Efforts at this level should feel very easy and are meant for recovery runs. On some extremely hot or humid days, you may need to slow way down to stay in this zone. Running in this zone provides minimal risk yet still provides benefits such as expedited recovery from harder efforts.
Zone 2: Endurance – 60-70% HR max
This is your ‘bread and butter’ training zone, where you should do most of your easy runs and long runs. This is also where you get the biggest ‘bang for your buck’ in terms of aerobic and endurance training benefits.
Zone 3: Tempo – 70-80% HR max
Often reserved for comfortably hard efforts such as practicing marathon and possibly half-marathon pace, this is a so-called grey zone that provides few physiological benefits (but does provide important psychological ones). Avoid running your easy runs at this pace and note that on some days, your typical easy or endurance training runs could end up in this zone because of the added stress of the heat.
Zone 4: Threshold – 80-90% HR max
This is also called the lactate zone and refers to the point at which the body fatigues in an unsustainable way. Usually, running at 5K to 10K race pace will land you in this zone and it is an important training zone for improving your fitness. Hard tempo runs of 15-45 minutes within this zone will help to improve your lactate threshold.
Zone 5: VO2 max – 90-100% HR max
Efforts at this level are only sustainable for a very short period, perhaps a few minutes at most. In ideal conditions, you can run at 1 mile to 3,000m race pace but in less than ideal conditions, even 5K repeats can land you in this zone. This is sometimes called the maximum, “red line” or anaerobic zone.