For the past couple of months I’ve been lifting weights three days a week and doing cardio sprints the other two or three days a week. “Cardio sprints” is my coined phrase and seems pretty applicable to the exercise but also pretty generic, hence this descrption.
Requirements for Casey’s Cardio Sprints: treadmill (or decent outside running weather) and a heart-rate monitor.
I start out with a 5 minute walk to get warmed up. Then I bump up the speed to 8.5 MPH and run until my heart rate is at 170 BPM (~90% of my maximum heart rate). After my heart rate reaches 170 BPM I run for 2 minutes then lower the speed to 2.5 MPH. After my heart rate drops below 160 BPM (~85% of my maximum heart rate) I continue for another minute, then ramp up for the second sprint at 9.0 MPH. The “2 minutes run at > 170 BPM” followed by “1 minute walk at < 160 BPM” pairing is one sprint. I do 5 of these at different running speeds finished off with a 5 minute cool-down. Note that during the running phase my heart rate goes way above 170 (between 180 and 200 depending on the speed and the day) and during the slow phase my heart rate goes way below 160 (usually down to the 130s).
When I first started I was doing all the running at 8 MPH and it would take me a while to both get my heart rate up to > 170 and then a bit to get it back to < 160 so the entire workout took at least 45 minutes. [Odd observation: initially my heart rate always seemed to get ‘stuck’ at 166 on the way up to 170. Not sure what the deal was but it would never fail to pause for a bit at 166.]
Now I’m doing my first run at 8.5 MPH and incrementing up 0.5 MPH until my last run is at 10.5 MPH. My heart rate ramps up and down much faster now so my entire workout is much closer to 30 minutes including warm-up and cool-down. The last 2 minutes at 10.5 MPH is killer and the first time I tried it I was only able to wheeze out 1 of the 2 minutes. Now I’m able to finish the entire 2 minutes with less wheezing at the end.
I feel like I’ve “mastered” this variation of the sprints — next week it’s time to mix it up a bit. I haven’t decided if I want to aim for a higher BPM threshold (180 BPM would be 95% of my maximum heart rate), increase the speed, or just do something else altogether.
Maybe it’s time to get back on the rowing machine…