I've modified my training, not to take 20 minute rests, but to take many short rests in my warm-up. Currently I'm indoor-rowing only for warm-up. I do

500m rowing (approx two minutes).
complete rest till pulse rate about 90

Repeat the above four more times, each time beating the previous 500m time by 1-2 seconds. I then do the same thing all over again, but substitute 30s all-out sprints for the 500m row.

My BG increase is about 10 points or lower. By the way, before I started this new scheme, I recorded my BG before and after 20 minutes of HIIT, and it went up 60 points. Don't know if that was just a bad day or not because I switched to the new style after that.

Larry (or anyone) - I know you are practicing the 20 minute rests, any opinion on multiple short rests versus one longer rest?

Hi Paul,

I think that any sustained (~15 - 20 min) intense (anaerobic) workout will cause a spike in blood glucose that can not be avoided during exercise for the reasons I explained earlier. To moderate those increases we must permit our insulin response to return, and to do that requires a reduction in the level of intensity into the aerobic range. So long as the rest periods are long enough to permit the pulse rate to lower into the aerobic range, and are sufficiently long for the insulin response to reduce the spike, your approach will work. There might be an exception to this if the workout extended into several hours to near exhaustion. When that happens even moderate or low intensity exercise might cause undue stress on the body causing it to breakdown muscle tissue to glucose.

Theoretically if your approach permits you to extend the total length of your workout, at a pulse rate elevated over the resting rate, it might result in superior weight loss and improved control because your metabolism would be increased over a longer duration. I have no idea whether this routine would lead to better performance or an increase in lean body weight over other routines.

From a practical standpoint most people can't spare large amounts of time exercising. If you can its certainly worth a try. Even my one or two rest periods have greatly increased the time I spend in the gym.

Larry

Ifchanin - you might want to check just a few threads down(Climbing on Mt Rainier), intense sustained exercise can drop blood sugars, admittedly mountain hiking is a little more extreme than a gym. My interest in this experiment was to see how much carbs I could use without raising BGs.

Larry,

It's clear, and thanks for the explanations throughout the thread. To summarize, anaerobic exercise turns off insulin response at the same time that the liver is releasing glucose into the blood stream. Hence an increase in BG in proportion to the time spent in the anaerobic state. Rest periods, whether a 20 minute rest or multiple short rests between short sprints, allow insulin to turn back on and reduce blood glucose.

(BTW my multiple short-rests were not motivated by a training reason, it's only that there is no good place to rest in my gym for 20 mins or to walk outside.)

That's one key issue - keeping BG down during exercise. Another one is what kind of training best improves insulin sensitivity and why. My short understanding of insulin resistance is that insulin is signaling cells to accept glucose, but too few receptors on cell membranes are acting on the signal. It seems resistance training gets most recommendation for improving insulin sensitivity (my simple guess is that it's creating new muscle cells with lots of insulin receptors ready for more weight training). But Dr Bernstein is keen on sustained anaerobic exercise like elevated treadmill (maybe motivated more for T1 reasons than T2), and aerobic exercise also has good effects. That seems to cover most possible activity, but I haven't read anything about how to mix the different types for best effect. Not sure it's an unknown area or if there is any research there,

Paul.

Hi Rob,

Very impressive!

However, what I specified by "intense" was specifically anaerobic exercise. As I said during anaerobic exercise we have little if no insulin response, but our liver is still dumping glucose into our blood stream to deal with the exercise energy requirements. So we experience a glucose spike. It is after the exercise, during recovery that insulin response kicks in and reduces the blood glucose. Repeated bouts of anaerobic exercise (or vigorous aerobic exercise for that matter) followed by recovery periods, will quickly result in low blood sugar, particularly as in your case, when there is a large net negative caloric intake for a relatively long duration. In fact, we can reproduce low blood glucose levels even without the intense exercise associated with climbing Mt. Rainier, simply by not eating.

Larry

Hi Paul,

Yes.



Yes, but it is the duration of the rest that is critical. As I said in my earlier posting, the duration of the rest would have to be long enough to permit the insulin response to reduce blood glucose response triggered by the intense exercise. I used 30 minutes of exercise and 20 minutes of rest because it matched the scientific study that I referenced, and coincidentally it takes me about 30 minutes to compete a set of exercises. I only tested this routine once, but it worked fairly well.



Yes, most authorities believe that "resistance" training is superior to "aerobic" training. But there is a big difference in doing strenuous weight lifting in which you are repeatedly in the anaerobic mode for maybe a few minutes followed by recovery, versus running for 20 minutes at 80% VO2 max.

Of all the diabetes authorities I regard Dr. Bernstein as the most credible. However, I don't think he's infallable, nor do I consider him an expert on exercise. Furthermore, thet fact that he is a type I diabetic can't help but color his recommendations. He's learned to adjust his insulin dosage to account for sustained anaerobic exercise. I don't have that means of adjustment yet, and I hope to defer it for as long as reasonable. Being able to do HIIT with minimal blood glucose spikes isn't a compelling reason for me to start taking insulin.

In addition, as I have mentioned a few times earlier, due to his exceptional conditioning, it is quite likely that his exercising pulse rate, while indicative of an anaerobic mode in the vast majority of 73 year olds, may not in fact be high enough to place him in HIS true anaerobic mode.

As far as mixing the various types of exercise, I haven't seen any studies aimed at type II diabetics either. I think that resistance training should be our primary exercise. Ideally we should vigorously exercise almost every day. However, since our muscles need to rest between workouts it is not advisable to do resistance training daily. Therefore, I think we must settle for aerobic exercises on off days. It will increase our metabolism, but not as much as resistance training. Next we have to consider whether we need to lose weight, gain weight or maintain weight to determine how much aerobic exercise. In my case, I'm trying to gain weigh so long bouts of aerobic exercise would probably be counterproductive. For a person with a lot of extra weight to lose, perhaps more protracted aerobic exercise might be better.

Larry

I do moderately intense aerobic shadowboxing for 3 minutes about an hour after a meal.It will lower my glucose levet 25-40 points maybe 70 percent of the time.It has no effect
for maybe 30 percent of the time.10 minutes of power
weightlifting in the evening raises my glucose slightly(maybe
10 points) but it subsides after about an hour.That's the
way it works with me these days.
Cheers
Eddie

Hi Eddie,

Just three minutes of exercise resulting in a 25 - 40 point decrease certainly is well worth the effort. I think I'll try to get in the habit of doing some sort of exercise after eating.

Obviously a 10 point increase shouldn't be a cause of concern, unless one's pre-exercise blood glucose levels were already high. This discussion of resting between exercises is really aimed at avoiding exercise induced increases that simulate a large, high carbohydrate meal.

Larry

Any thoughts why it sometimes works and sometimes not i.e. is there any identifiable factor?

Something this discussion made me think about - the standard medical blood glucose tests are mostly connected with food (or lack of it) - fasting BG, GTT, two-hour post-prandial BG. (HbA1C is different but cannot be done by the individual). But maybe there are also some useful tests that could be done on exercise-induced change in BG. When I read your mail, I was already wondering whether I could define a standard repeatable exercise for myself, and measure my BG before and after the exercise to get the rise or fall, then check if it was a stable sort of measurement so that I could use it to look for improvement over time. But it seems like your experience at least shows that exercise results vary from day to day.

One of the things that slows down this forum is a lack of regular contributors. Do we perhaps have the critical mass to do something like pauleo suggests. The bunch of us could start setting up some parameters and do some testing. To some extent it would be anecdotal, but I think possibly significant anecdotal. Rob

Hi Paul,

Apparently HbA1C can be done at home.

Check your A1C level at home

However, as you know having this type of 3-month average reading on demand still wouldn't offer any insights as to why a particular exercise bout was ineffective in reducing blood glucose over the period of an hour or so.

Needless to say there are other variables that could have effected Eddie's results other than the duration and intensity of his exercise. The most likely one is a difference in the size of the meal, the carbohydrate content, and the composition of the meal, % protein and fat. Other contributing factors might be a difference in how active he was earlier in the day.

The point is, HbA1C is the definitive test to look for improvement over time. However to improve HbA1C we must improve our daily blood glucose profiles. To do that we must use our "instanteous" blood glucose monitors multiple time during the day to get visibility of spikes and from that infer what we did to cause them. The usual means for achieving this is to keep a log of relevant activities (exercise, duration & intensity; meals, amounts & composition; medications & supplements; etc.) during the day accompanied by before and blood glucose readings.

Larry

Hi Rob,

Interesting idea. It may be worth a try if the objective was specific enough, and the variables were sufficiently controlled.

However, aside from the differences in our metabolisms, there's a lot of other factors that might make drawing conclusions from comparisons of limited value. For example, variations in type of exercise, level of fitness, diet objective, i.e. weigh loss, gain or maintenance, age, medication, etc.

Larry

About the exercise test, I'll give a specific example of what I was thinking about.

Say I go to the gym on day 1 and my BG is 90 before a (fixed, repeatable) exercise and 100 afterwards.

On day 2 I go to the gym and my BG is 100 before the same exercise and 110 afterwards.

Day 3 I go and BG is 95 before and 105 afterwards.

This would be typical in that my starting BG varies from day to day because I eat different things, I arrive at the gym at different times etc. But in the example above, the change in BG caused by my fixed repeatable exercise is always 10. If this is the case, that change in BG is really acting as a reliable indication of how my body is reacting to the exercise, so I am getting some useful information. Also if I keep tracking it over weeks and months and see a slow decrease from 10 to 9 to 8 etc, then I have evidence of an improvement.

That's the idea - is the change in BG induced by a fixed exercise a stable type of number, that factors out the everyday fluctuations? (I think it's more likely that the change in BG fluctuates all over the place, but this is what I was wondering about).

Of course you couldn't use that number to compare between different people. That's not what it's for, it's to test one individual's improvement.

Also it's true that we already have measurements like FBG that allow one to track day-to-day progress so maybe exercise-related BG measurements don't add anything.

Hi Paul,

Gotcha.

If you're concerned about improving blood glucose control as it relates to intense exercise, I think for many of us the approach you describe needs to be refined a bit. First you need to test your assumption about multiple, small rest periods. To do that you need to measure your before and after blood glucose for each intense session to see if your levels are progressively getting higher or not. If so, you need to increase the duration of the rest. (Obviously if we're only talking about 10 points for the entire workout, then it probably doesn't matter much. However, some of us have experienced quite severe spikes that need to be controlled.) Once we've optimized the ratio of exercise to rest, then perhaps a before and after workout trendline might be helpful.

Agreed that other measures, such as daily fasting blood glucose, help to determine our day-to-day progress, but it doesn't really tells us much about whether our exercise method is hurting control. Therefore exercise related measures DO help us pin point a possible source of a loss of control. Once the optimum exercise to rest durations are determined, we only need to test before and after the workout, just like we do with meals.

Larry

Right. And what I was getting at is the whole idea of improving insulin sensitivity, by identifying a way to measure improvement, and then trying different mixes of exercise to see what is most effective.

The information about rest periods in this thread has been very useful and directly helped me. It feels like a good success. But then, thinking about it, this was a situation where simple testing was sufficient - we can use a BG meter to test on the spot before and during exercise, to get immediate feedback on what works. It is obviously a much more difficult case to figure out changes in insulin resistance, because the changes are long-term, and because every aspect of life is influencing this not just exercise.

So what I was trying to get at, or wondering about, is if it's possible to somehow isolate some exercise related measurements that relate to insulin sensitivity, and then just work on them. It's an attempt to simplify the problem, and get food and tiredness-level and stress-level etc out of the picture, to make it easier to figure out the most beneficial exercise.

I did look around for some material on insulin sensitivity at amazon yesterday. Sadly the popular books all look like they won't add anything to what I have already got (Dr Bernstein and a couple of others), while the academic books on diabetes and exercise cost a fortune. It's a pity because there's obviously an audience of lay-people who want this info to try to apply ideas in practice.