Attempting To Lower My Bodyweight Set-Point Using Sprints
The way I sleep, exercise, manage stress, get outside, and eat makes by body very happy in the 145 to 155 pound range. But now, I am attempting to lower my bodyweight set-point. I’m going to try and make by body want to be faster and leaner to evade imaginary predators. I am doing this by incorporating sprinting, i.e., running as fast as I can for as long as I can (aiming for 20-40 seconds), into my day. I set out on this venture 10 days ago, sprinting in the morning in addition to my normal activities (3 intermediate-level yoga classes per week, the occasional pilates class, active play and slow walks with my kids, gardening and our weekly family hike).
There seems to be alot of ways to incorporate sprints into your routine (and perhaps no “right” way). The usual approach is to incorporate sprinting into a High Intensity Interval Training (HIIT) workout (where sprints and other intense cardio are alternated with strength training exercises). I decided not to use HIITs because I wanted to incorporate sprints into my day with the smallest possible time commitment (and I am not interested in giving up yoga to make more time). And I have the benefit of having a treadmill in my basement. So, my initial approach was this: I sprint on my treadmill (with a small incline) in three “bursts”. I give myself 1-2 minutes to catch my breath in between. I sprint for just over a minute total between those three bursts. I throw in a set of push-ups and/or inverse pull-ups afterward (I can’t do a full pull-up so I jump up and then lower myself down as slowly as possible). I like to think this mimics being surprised by a predator, sprinting to a tree and then climbing up! Simply adding this small amount of intense exercise to my day had a profound effect on my hunger and energy levels, but, as I will get to in a minute, this approach needed some modifications to make it sustainable for me.
The difference to my appetite was nearly instant. I couldn’t believe how little I wanted to eat the very first day I sprinted, literally half of what I was eating before (my appetite did increase after about a week, but still a little lower than before). I was also extremely thirsty, probably drinking 5 times the water I normally do (which has continued). I was amazed at how quickly my sprint speed and anaerobic stamina increased. In my first week, I was able to increase my speed by 0.2-0.6 miles per hour faster every day (my first day I ran at 7.2 miles/hour and this morning I ran at 9.5 miles/hour). I started losing weight and I was so excited. But on Day 5, I started to notice the strain in my ligaments, especially in my groin and the back of my knees (a bit in my shins too). I realized that my joints just can’t take a cold sprint, especially first thing in the morning. So, I took a rest day (on Easter Sunday, when I really could have used the appetite suppression power of sprinting!). Then, I added a 4-5 minute brisk walking warm up, and a 2-3 minute cool down and a few more stretches afterward and in between. I also stopped pushing myself to increase my speed, but instead noticed an increase in how long I could sprint each time (before I was struggling to hit 20 seconds, and now I can hit 30 seconds for my first burst and 20-25 seconds for the subsequent two). I give myself 2-4 minutes to catch my breath in between sprints, using this time for a set of lunges, push-ups, inverse pull-ups, body rows or push-up burpees and a little stretching. My total time commitment increased to about 15 minutes, but the strain on my joints is decreasing. You may have noticed that this looks alot more like a short HIIT workout now.
The first day, I felt a burn in my chest that lasted for several hours after my first sprint. But I didn’t experience that same burn beyond that. I had one rough day on Day 3 where I seemed to hit a metabolism transition point. I hadn’t properly listened to my thirst cues the day before and just didn’t drink enough. I woke up with a killer headache (my first in months) that only went away after a strong coffee and two liters of water. That same day I noticed a distinct shift in my bowel habits (I know this is TMI, but if you’re going to try this, you will appreciate the warning!) to an obviously faster transit time (this settled down in a couple of days). I went from simply not being hungry to being slightly revolted by food (the revulsion goes away when I become truly hungry). That was also the day that my weight started decreasing. In the last 10 days, I have lost 4 pounds in spite of indulging completely in the excesses of our paleo Easter. Yes, some of this may be water weight, but I’m also seeing significant strength gains. My new scale, which measures body composition, just arrived this morning (you’ve never seen anyone so excited about a scale!). It estimates my body fat percentage at 26% and muscle mass at 37% (which are considered “normal”! Woot!). These are the numbers I will be tracking from now on to gauge my success.
I am really happy with how sprinting (and the strength training exercises I’m throwing in) is affecting me. My appetite is still lower than before (and my carb hangover from Easter only lasted one day!). I seem to be craving very high quality foods (sardines, liver, heart, bone broth, kale, beets, coconut oil…) and preferring most of my vegetables raw to cooked. It also seems easier to keep my intake of fruit and other sweet stuff very low (at least now that the creme eggs are gone). I am much warmer all the time (and sweaty for a while after a sprint, although not for as long as I was the first couple of days). I am sleeping much more soundly and tired earlier in the evening (so going to bed earlier). I’m also falling back asleep much more easily if I have to get up in the night with one of my kids (which seems to be frequent these days). This is really amazing when you consider that the length of time that I am exercising is so short! This definitely emphasizes that exercise is not about burning calories but about regulating hormones. I don’t know if I will continue losing weight, but I feel good and optimistic enough to continue (and willing to change things up again if I need to). I really do think that this is going to work (although, maybe more slowly than I had hoped). Heck, I feel optimistic enough that I’m online browsing for 2-piece bathing suits for our beach trip (and I haven’t owned a 2-piece bathing suit since I was 8 years old!). But, even if I don’t lose any more weight (or buy a 2-piece bathing suit), I am enjoying the physical challenge, the increase in strength, and how I feel.