Training with heart rate in mind

I took Jacki's suggestion a few weeks back and started interval cardio training on the treadmill. One disclaimer, this is not her recommended workout, just a version this novice made up out of the blue since I couldn't exactly recall her post. My 5k treadmill workout goes something like this: after a fast walk warm-up, I jog at 5.6 mph for about five to eight minutes. Then I amp it up to 6.1 mph for two minutes, back down to 5.6 for two minutes, increase to 6.6 mph for two minutes, return to my 5.6 mph baseline, then a final two minute push at 7.1 mph. I return to 5.6 mph for several minutes to recover, then repeat the sequence. Admittedly, I typically feel like I'm going to toss my cookies after the 7.1 sprint, so I walk a couple minutes before heading back up to 5.6 mph.

It's at the 7.1 mph mark with legs a flyin' and lungs a heavin' that my heart feels as if it'll beat right out of my chest. It made me wonder, "What exactly is my heart rate at this painful cardiovascular apex?" Unfortunately, to find out I had to quickly slow down to a 4.0 mph walk or less and grab hold of the treadmill sensors (sensors don't work unless you're at a walking pace -- safety thing). Turns out I was at 176 beats per minute, over 90 percent of my estimated maximum heart rate (MHR) for this 40 year old.

Check out this informative article on increasing your fitness and performance by training with heart rate in mind. Understanding the five heart rate zones can better assist you in ramping up your fitness level steadily and strategically to build cardio endurance and strength, while preventing injury and fatigue. Here is a short recap on each of the five heart rate zones:

• Zone 1/Recovery: Easiest training level, a slow walk after a hard run.
• Zone 2/Easy Aerobic (60-70 percent MHR): Endurance and aerobic capacity improve in this zone, and since lactic acid buildup is low, you can hang out in Zone 2 for a longer, more comfy amount of training time. Multisport athletes (e.g., Ironmen/women) train mostly in this zone.
• Zone 3: Intensive Aerobic (70-80 percent MHR): Possibly the most effective zone to improve cardio fitness. Lactic acid buildup increases, so fast-twitch muscle fibers step in to aid slow twitch fibers. Muscle strength is improved. Not a good zone for triathletes to predominantly train within as it's not easy enough for endurance/recovery and not difficult enough to improve overall performance.
• Zone 4-5a/Threshold (80-90 percent MHR): You're feeling the pain here, breathing hard, and your anaerobic or lactate threshold increases, ultimately improving performance. You can train your body to tolerate lactic acid and up that anaerobic threshold with proper training in this zone -- an important niche for multi-sporters.
• Zone 5b/Anaerobic Endurance (90 percent MHR and above): You know when they start adding lower case letters next to numbers that things are getting ridiculously difficult (e.g., 5.13c rock climbing routes)! A Zone for the very fit, you can only train in 5b for a short period as lactic acid spikes, making muscles scream for oxygen. Too much 5b can result in injury or overtraining. You clearly need proper rest after training within 5b -- do some more research to find out how to utilize this zone properly -- the article did not elaborate on specifics.

No doubt, those 5k treadmill interval workouts remind me of dreaded windsprints at the end of high school basketball practice. Windsprints were incredibly stitch-in-your-side painful, but became an enjoyable exercise as the season progressed. After learning about the five zones, I used to hang out within Zone 2 on the treadmill way too much. While I'm no fitness expert, those interval treadmill workouts do have me spending time in higher zones I rarely flirted with previously. I'll keep them up -- I'm ultimately boosting my cardio and strength.