Dear Mark: How Many Sprints Per Week, How to Play and Train with Babies, and the Best Nighttime Snack

Baby finalFor today’s Dear Mark, I’m answering three questions. First, how often can a person sprint safely and effectively? There are many factors to consider when determining the amount of sprinting a person can handle each week, like stress levels, sleep, and other training, so it’s tough to give a specific number. Next, what are new parents supposed to do for physical play and exercise? Aren’t babies fragile, helpless things? No. As you’ll see, it’s possible and even desirable to expose your young children to intense (but fun) play and exercise and introduce elements of cautious risk-taking into your time with them. Finally, what’s the best nighttime snack alternative to nuts and dried fruit?

Let’s go:


I currently sprint every 4 or 5 days (bike sprints, total time on bike 22-25 min, with 6-8 30 sec sprints). I also strength train twice a week. I know we only need to sprint every 7 to 10 days to maintain the health benefits, but I love sprinting. As a former chronic cardio Type A, I fear I’m going to increase my sprinting frequency until I’m doing it everyday which would clearly not be good for me. What’s the most frequent I can do them without it becoming detrimental to my health?

If you want to sprint more often, it usually comes out of the rest of your training.

Of course, many of the pro-sprinting/HIIT studies use multiple sessions per week and get great results. What gives? In order to exclude any confounding variables, they generally forbid participants from engaging in other exercises. So in a HIIT study, you’ll just do HIIT and nothing else on the side. You won’t lift weights, or go on hikes, or any other formal exercise. You’ll be focusing on HIIT and HIIT alone so as to isolate the effects of the experimental condition. The absence of other training coupled with the total dedication to the program allows adequate recovery.

If you weren’t doing anything else, I’d say you could get away with three or four sprinting or HIIT days a week. I think, though, that optimal fitness is achieved through a more well-rounded approach that includes lifting heavy things, play, lots of slow moving, and yes, sprinting (or HIIT). All those activities require recovery time. We can and do learn from fitness studies, but in reality we can’t just take what studies do wholesale. We would fail, or be required to sleep twelve hours a day, or eat 4000 calories, or go back to college and shirk our responsibilities.

You must also consider the subjects of these studies, which usually use students because they have a ton of free time and often need the money.  More free time means more recovery time and being a student means less psychological stress (except for perhaps during finals), which can also impact your workout recovery. Worrying about getting laid or what to wear to the frat party on Friday is less stressful than worrying about bills, dealing with family issues, or having to commute an hour each way every day.

If I had to give you a figure—which I can’t really do given the paucity of information I have—I’d say you can probably get away with an extra sprint session per week given that you’re only lifting twice a week. However, if you’re truly going all out 6-8 times for 30 seconds on a bike each session, that’s like doing two Wingate tests, which researchers use to determine peak anaerobic power and capacity. People who’ve done the test (4 30-second all out bike sprints) often rate it as the hardest thing they’ve ever done. Puke buckets are a standard feature of the Wingate test. So ask yourself if you’re really going hard enough. If not, maybe drop it down to 4 30-second sprints and really go for it. Then see if you’re still interested in more sprinting.

Most people who want to sprint all the time aren’t really sprinting.

Although I walk and get sun everyday, I’m struggling to figure out the ‘play’ aspect of the 21 day challenge. I have a 7 month old baby girl that is truly a blessing, but anything I do…She needs to be able to come along! Please, any ideas? Thanks!


Seconded! I have an 11 month old and I’m wishing so badly that I could climb trees and sprint (both things I used to thoroughly enjoy) while holding him.

There are tons of things you can do with your little ones.

You can still climb trees. Look, maybe your pediatrician wouldn’t recommend this. Maybe your mother-in-law (or wife or husband) will flip out on you. But as long as you’re careful, you can climb trees while holding your kid. Maybe not to the top, or even halfway, but you can certainly monkey around in trees while staying close to the ground. Get the kid used to being in a tree. Let the kids climb the tree themselves. Show them how to hold on to large branches and hang from smaller ones. Leave the kid at the bottom of the tree and see how quickly you can reach the top and get back down (unless dingos abound, no one’s going to steal your baby) before the cries start. Do this often enough and your kid will realize that being away from you for a minute or two isn’t the worst thing in the world and everything will actually be okay (you might learn something similar).

Sprinting? Yeah, you can sprint. One of my employees did extensive hill sprints while holding his sub-1 year old daughter on a regular basis. Clutch the kid like a football, hug them to your chest, keep a hand on their head to prevent flailing, and just go for it. Hills seem to work better, since you’re falling a shorter distance and there’s less of a jarring impact.

Once the kid can stay on your back and hold onto your shoulders/neck, take them for a ride. Crawl around with them on your back. Spin around 18o degrees while crawling, moving ever faster as they get better at holding on. Do some hops from a squat position, a la Darryl Edwards’ bunny hops. Kids love this, it builds their strength and confidence, and it’s great for your fitness.

Kids are great weights. They’re like medicine balls that get heavier as you get stronger. Swing them like a kettlebell (cradle the head/protect the neck/watch the splaying legs). Toss them. Squat down and push press them up into the air, catching them in a full squat. Single arm press them overhead. Do Turkish get-ups.

Roughhouse. Roughhousing is a lost art. Chances are your kids’ friends won’t be allowed to do it, so you may have to toss your kid around a bit to teach them. Do so lovingly and playfully. Here’s a nice example of daddy-daughter roughhousing from Rafe Kelley.

Wear your kid. You’d be surprised at how much you can do with a kid attached to your chest (or back).

What else can you think of? Be creative.

I am a big night snacker. Dried fruit and nuts have been my go too but I don’t want to over do it. Trying to find something to replace and then eventually get over the snacking.

Herbal tea jello.

Brew non-caffeinated tea of your choice. Maybe a chamomile or ginger tea.

Stir in powdered gelatin until it dissolves in the hot tea.

Add a touch of sweetener, like raw honey or stevia.

Refrigerate until solidified.

The gelatin (specifically the glycine content) will improve the quality of your sleep (and make you less groggy after sleep deprivation). You’ll get a fun treat before bed. Win-win. This also works with caffeinated liquid, too—coffee, green/black tea—if you want something earlier in the day.

TAGS:  dear mark

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending more than three decades educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates flavorful and delicious kitchen staples crafted with premium ingredients like avocado oil. With over 70 condiments, sauces, oils, and dressings in their lineup, Primal Kitchen makes it easy to prep mouthwatering meals that fit into your lifestyle.

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