Here’s how to get the most out of both rounds.
When you have a busy schedule, fitting in your workouts calls for creativity. Sometimes that means commuting on foot or zipping through your morning routine to make time for a lifting session. And sometimes it means doubling up.
Doing two shorter workouts instead of one longer one has its pros. “The body adapts to the demands placed upon it, so getting a second training session in a single day makes your body that much more fit,” says Justin Mager, MD, a San Francisco-based exercise physiologist and a member of the Equinox Health Advisory Board.
That said, adding a second session can push you from adaptation to burnout and injury, making it even more important to hydrate; get enough sleep; and limit other sources of stress, which can stall progress by increasing cortisol, inflammation, and blood sugar levels, says Alex Zimmerman, CSCS, director of the Tier X program at Equinox. You should also stay alert for signs of overtraining, like fatigue, plateaus, and decreased performance.
Here’s how you can master the art.
Space out your sessions.
Aim to do the first workout in the morning and the second in the afternoon, but not so early or late that they disrupt your sleep, says Zimmerman. Ideally, you’d exercise around 8 a.m. and 4 p.m.
Do two of the same type of workout.
If you have a specific goal (like running faster or building muscle), doing two different types of exercise in a single day can activate competing pathways and slow progress, says Michol Dalcourt, founder and director of the Institute of Motion and a member of the Equinox Health Advisory Board. That’s known as cellular interference.
Instead, do either two strength or two cardio routines, depending on your goals. (It’s still important to get your heart rate up if you’re a lifter and to spend time in the weight room if you’re a runner—just save those workouts for days you have only one session planned.)
But don’t double up on HIIT.
Doing them back to back with less than 24 hours rest in between leads to diminishing returns. “The nervous system can only handle so much stress before it starts to hurt performance,” Zimmerman says.
Even if you’re a seasoned lifter or triathlete, you can take the intensity down a notch for your second round. “Sometimes people who train hard lose the opportunity to connect with the body,” Mager says. If you’re feeling more zen in the afternoon, balance out your routine with yoga or an animal flow.
Open your chest and back.
Athletes who spend long stretches of time sitting at work should take frequent breaks to do back- and chest-opening moves (Mager used to have a pull-up bar in his office for this purpose), or build in other moments of mobility.
Activate your vagus nerve.
If you have the time (and place) to nap at work, great. If not, you can speed up recovery by doing other things that stimulate your vagus nerve, which flips your body between fight-and-flight and rest-and-digest modes, Dalcourt says. You can activate your parasympathetic nervous system with deep breathing exercises, meditation, gentle yoga, and even laughter.
Compression boots, foam rollers, and infrared or regular saunas can also prepare your body for round two, Zimmerman says.
Fuel for your afternoon session.
Some athletes opt for low-carb or fasted workouts while others aim to eat one to two hours pre-training. There's no right or wrong, but one thing is clear: The longer your session, the more energy (read: fuel) you need. And the more you get from whole, unprocessed foods, the better, Zimmerman says.
Your muscles have enough glycogen stores to make it through your first round of exercise if it lasts 90 minutes or less. But you’ll need to gear up for the second. “Fuel is important after the first workout to build up the body’s energy supply,” Dalcourt says. "It’s basically like filling your car up with gas."
Time your macros right.
Eat protein and carbs in the hour following your a.m. workout, when your cells are more permeable and your body can absorb the nutrients more easily. (Follow this rule after your afternoon session, too.) Exactly how much you need to eat depends on factors like your weight, your goals, the type of exercise you're doing, and what you eat the rest of the day. But generally speaking, aim for a three- or four-to-one ratio of carbs to protein post-workout.
Tune in to your body.
There’s always room for personalization between sessions, Mager says. You might find you feel better if you eat lighter and allow your body to tap into existing energy reserves; if you feel too weak to tackle the next session, consider eating a meal or snack beforehand.
Always gauge how you feel before committing to a two-a-day. “Building your body down without building it back up can be very harmful to your performance and health,” Zimmerman says.