Insulin does a lot of important things for us. It pulls glucose from the blood and fritters it away into our cells to be burned for energy or stored as glycogen. It prevents hyperglycemic toxicity to neurons, pancreatic cells, the arterial walls and the generation of excessive levels of reactive oxygen species. It even promotes muscle protein synthesis and helps augment muscular hypertrophy, especially following resistance training. Clearly, we need insulin. Without it, we’d die, as type 1 diabetics readily do without an exogenous source.
But this process goes off the rails when our cells become resistant to the effect of insulin over time. We secrete too much. Our levels remain elevated. It becomes harder to burn body fat. In fact, we end up in even more efficient fat storage mode.
I’ve shared about nutritional means to enhance insulin sensitivity in the past. What about other non-dietary strategies?
Since insulin resistance is often the body’s response to energy excess (too much energy in), losing weight (increasing energy out) improves insulin sensitivity. Losing abdominal fat is particularly effective for increasing insulin sensitivity.
Lifting heavy things, particularly with great intensity, improves insulin sensitivity by an interesting mechanism: non-insulin dependent glucose uptake happens immediately after the workout, which allows your muscles to replenish glycogen without insulin. According to some researchers, “the effect of exercise is similar to the action of insulin on glucose uptake.” I’d say not having to secrete any insulin makes you effectively insulin-sensitive.
An overloaded, energy-replete cell is an insulin resistant cell. An empty, “starving” cell is an insulin sensitive cell. Any exercise that burns glycogen and leaves your muscles empty and gaping for more will necessarily increase insulin sensitivity.
Glycogen depletion occurs locally: high rep leg presses will deplete leg muscle glycogen, but they won’t touch glycogen in your arms, chest, and back. To fully deplete all the glycogen, you need to do full-body movements.
CrossFit WODs and other similar metcon workouts that have you doing pullups, squats, sprints, pushups, box jumps, and other compound movements—at high volume, in the same workout, and with minimal rest—will drain your glycogen stores and reduce the amount of insulin you need to replenish them.
Maybe it’s the quieting of the sympathetic nervous system, the “flight or flight” stress pathway. Maybe brief glimpses of bodhi reduce the amount of insulin required to dispose of glucose. Whatever’s going on, meditation (and likely other relaxation response inducing activities) improves insulin sensitivity.
So, researchers might have used intranasal oxytocin for their purposes. But oxytocin is what we secrete in response to positive social interactions like sex, good conversation, dinner parties, breastfeeding, cuddling, and petting animals.
If you’re coming from a place of already-adequate sleep, getting better sleep isn’t necessarily going to help your insulin sensitivity (although it might confer other benefits). It’s the absence of adequate sleep that destroys insulin sensitivity. By sleeping well, you’re restoring what was lost.
One study found that altitude hiking at 4500 meters improved glucose tolerance and insulin sensitivity. This isn’t feasible for everyone (4500 meters is really quite high, and not everyone lives near a suitable mountain). And, in truth, some people just aren’t ready to climb a mountain and hike around (in the study, some participants with low DHEA-S levels didn’t get the benefits), but it’s one way to improve it. Find the closest challenge you can in your region of the country.
While training of any kind promotes better insulin sensitivity, training in the fasted state enhances this effect. One study found that relatively high-intensity “cardio” performed while fasted increased subjects’ insulin sensitivity beyond the group who did the same training after a carb meal, even in the context of a normally obesogenic high-fat, high-carb diet.
As the Primal Blueprint fitness concept of slow movement suggests, a simple walk can be quite powerful, particularly if you string them together to form a daily walking habit. A walk is good for glucose control after meals, but regular walking can have impressive effects on insulin sensitivity.
In other words, stay active for life. In a recent paper, both sprinters (aged 20-90 years) and endurance athletes (20-80 years) had far better insulin sensitivity than sedentary controls. Absorb this point: insulin sensitivity didn’t decrease with age in the two active groups. Even the 90-year-old sprinter retained good insulin sensitivity. The sedentary controls? Not so much. That says it all, I think.
Thanks for stopping by today, everyone. Let me know your thoughts, additions and questions below.