Intervals, intervals, intervals! You keep hearing about how good they are for improving your cardiovascular health, increasing speed, and breaking through workout plateaus. Yet, you've been happily traveling along at a consistent pace — or maybe just afraid to max out your intensity. If you're ready to tackle intervals but sprinting scares the sports bra off of you, here's an easy workout where pace varies only slightly and never goes faster than 6.5 mph. Feel free to adjust the speed to your needs and have fun!

Time Pace (mph) RPE*
00:00-5:00 4.0 (15 min/mile) 1-3
05:00-6:00 5.0 (12 min/mile) 4-7
6:00-8:00 5.5 (11 min/mile) 8-10
8:00-9:00 5.0 4-7
9:00-11:00 6.0 (10 min/mile) 8-10
11:00-12:00 5.0 4-7
12:00-14:00 5.5 8-10
14:00-15:00 5.0 4-7
15:00-17:00 6.5 (9:14 min/mile) 8-10
17:00-18:00 5.0 4-7
18:00-20:00 5.5 8-10
20:00-21:00 5.0 4-7
21:00-23:00 6.0 8-10
23:00-24:00 5.0 4-7
24:00-26:00 5.5 8-10
26:00-31:00 4.0 4-7

*RPE = Rate of Perceived Exertion
For a printable version that you can take with you to the gym, click here.