I often take my clients to the track at Santa Barbara City College for their first interval session. This is a beautiful stadium that’s located right by the beach and there’s a spectacular view of the ocean from the top of the bleachers.
I’m a big believer in my clients doing cardio on their own. But for the first session, I like to take them out there to see how they do and explain the basics. That said, sometimes I work with clients, who are out of shape, get up to speed (so to speak).
One of the things I insist on, is that they wear their heart rate monitor out there, as I’ve detected problems that I would’ve missed without that monitor. It’s also a good idea to get a release from your doctor before you start.
Once you have your heart rate monitor, the first step is to determine your max heart rate. If you’re under 30, subtract your age from 220; and if you’re over 30, subtract one half your age from 205. Then multiply that number by 90 percent to determine target heart rate for high intensity interval training.
For example, the max HR for a 40 year old would be (205 – 20) = 185. And 90 percent of the max HR would be (185 x .90) = 166.5 beats per minute, BPM.
This basic formula, for determining max heart rate, is alright in the beginning, but keep in mind that it can be off by as much as 15 BPM. It’s a lot better to watch your heart rate and see your max when you’re actually training. And then use that.
I prefer the Heart Rate Reserve formula for determining target heart rate because it considers both max HR and resting HR (RHR) and percent of HRR equals percent of VO2max. Your RHR is your heart rate when you first wake up in the morning.
Heart Rate Reserve is the difference between your max HR and RHR. To calculate, subtract your RHR from your max HR. Then multiply by the desired percentage and add the RHR to the product.
For example, let’s take the 40 year old with a RHR of 50. HRR is (185 – 50) = 135 BPM. Target HR is (135 x .90) + 50 = 171.5 BPM. Notice that your heart rate’s a bit higher with this formula as compared with the other method.
Once you’ve determined your target heart rate, try to reach that intensity with each and every sprint. And then let your heart rate come back down during the slower recovery cardio to about 120 BPM.
Reaching the high intensity is necessary to achieve your goals, whether that means improving cardiovascular fitness (VO2max, lactate threshold, etc.) or dropping fat, or both.