Chapter 19
IN THIS CHAPTER
Going beyond basic training levels
Considering how adding or restricting carbs can affect your athletic performance
Figuring out why you may not be performing at the level you want
An athlete lives in everyone, even if you don’t consider yourself one. Being athletic is more a state of mind than anything else. That said, some people with diabetes are actual competitive athletes, taking part in professional sports, the Olympics, and collegiate and high school competitions.
This chapter is geared toward helping you if you’re a competitive athlete, but it’s relevant even if you’re just a more serious recreational one. Many different factors can impact your exercise performance — which can be gauged by how well you do and how good you feel while doing it — and now just may the time for you to get a performance tune-up.
Most of what you need to know about how to effectively progress your exercise training you can find in earlier chapters. How fast you progress should be an individual choice, but it does take time to establish an exercise habit and to increase your fitness level.
When your training has lapsed (or you’re just starting an exercise program), you benefit from an initial conditioning phase lasting four to six weeks. After that, you move on to an improvement phase for four to five months and then to a maintenance phase from six months on. If you already have a higher level of fitness, you may be able to shorten or skip the initial conditioning altogether.
When you already have a fitness base, additional gains happen if you work out more at the higher end of your intensity range. You can do short, harder intervals or sustained higher-intensity training. Intervals are equally effective, usually more motivating, and better for avoiding overuse injuries. (Discover more about interval training in Chapter 10.)
The overload principle of training states that you must keep challenging your body to have any further fitness improvements or gains in muscle strength, or else you just reach a plateau. Increasing your intensity works both during the improvement phase and after you reach the maintenance stage. At that point, your progress slows unless you continue to overload yourself by increasing your exercise intensity, duration, frequency, or a combination of these factors. If you’re as fit as you want to get, just work on staying that way.
In resistance workouts, you maximize your strength gains by doing 8 to 12 repetitions of each exercise (usually 8 to 10 different exercises) until you’re feeling fatigued. If you’re a novice at resistance work, you can start out with lighter weights or more-flexible resistance bands that enable you to complete one or two sets of 12 to 15 repetitions on each exercise, but use enough weight or resistance to feel at least somewhat fatigued by the end of the last set.
If you want to get a lot stronger, your goal should be to ultimately move a greater resistance fewer times (maybe 6 to 10 repetitions). Doing hard work produces more of an overload on the muscle fibers and brings you greater gains in muscular strength and mass.
The current resistance training recommendations don’t tell you how many sets of repetitions you should do on each exercise. It has been proven that you can gain strength by doing only one set — that is, you can get stronger doing just one maximal repetition one time a week — but you’re likely to gain more strength by performing two or three sets of each.
When doing more than one set per exercise, you can increase the weight or resistance on each successive set, slightly decreasing the number of reps each time the load increases (for example, doing 15 reps on the first set and only 10 on the second, harder set). You can also do it in reverse and decrease the weight while upping the reps on the second or third set. The idea is just to fatigue the muscles you’re using for any given exercise, and there are many ways to arrive at that goal.
When it comes to managing diabetes, how well trained you are definitely matters. How hard you’re working out affects what fuels your body is using. How long your activity lasts also makes a difference because some athletic events are so short that only the first and second energy systems come into play (see more on those in Chapter 4). They can be trained, but they don’t change as much with training as the aerobic energy system that relies heavily on carbohydrates and fat for fuel.
Here’s where your training state has the biggest impact. Being aerobically trained doing a specific activity can increase how much fat your body uses when you’re working out or competing. Most energy is supplied by carbohydrates when you do an activity at a somewhat-hard to hard intensity level. You use up a lot of stored glycogen from active muscles but also use some blood glucose.
After you’re more trained, if you’re working out at the same absolute intensity or pace, your muscles bump up their fat use. If you keep the relative exercise intensity the same by increasing your pace after you’re trained, then fat use increases only slightly.
All this information matters to how well you can keep your blood glucose stable and near-normal during exercise. You want to be able to use more fat and spare your body’s carbohydrate supply to do well in prolonged athletic events or endeavors. You want to avoid hypoglycemia that makes you slow down or stop so you can excel at your sport or any activity you choose to do with diabetes.
To a certain extent, you have to start the process over with each new activity you do, although being trained for one sport or activity does convey a higher starting level because your heart, lungs, and blood vessels may already be trained to operate at a higher level from your other types of training.
Almost all serious exercisers benefit from carbohydrate (carb) loading before long-distance events and carb reloading afterwards. Having an adequate intake of carbs at both times enables you to begin exercise with fully restored or even overfull stores of muscle glycogen (glucose stored in muscle and used during exercise).
The original carb-loading protocol before events was three to seven days of eating a high-carb diet (8 to 10 grams of carbs per kilogram of body weight). This diet was combined with a day or two of complete rest or a reduced exercise volume known as tapering.
But even a single day with a higher carb intake and rest or tapering can effectively maximize carb stores. Carb loading has been blown out of proportion and misapplied to all sorts of sporting events (like 5K walks) during which you have no risk of running out of muscle glycogen. You don’t need to spend a week, or even three days, over-consuming carbs and potentially lowering your insulin sensitivity and raising your blood glucose by doing so.
Most athletes make sure to take in plenty of carbs after their event or workout as well to restore glycogen in muscles as soon as possible. It can be different for people with diabetes, though, because it takes having enough insulin in your blood to restore glycogen effectively.
Not taking enough carbs after exercise can make it hard to do your next workout, but some people purposefully don’t eat enough to keep their insulin action higher for longer after workouts or sporting events. Insulin action stays higher until the glycogen in your muscles is fully restored. That usually takes one to two days when you eat a normal diet — but it can take much longer if you’re eating low-carb (head to the following section).
Even though your body improves its ability to use fat and ketones as a fuel for exercise when you’re on a low-carb regimen, fat is never your body’s first choice of fuels during moderate and intense workouts lasting more than a couple of minutes. If your body can get carbs, it uses them rather than fat, particularly as your workout gets more intense. It happens simply because using carbs is more fuel efficient — that is, you get more energy out of carbs for a given quantity of oxygen.
If you’re eating enough calories to cover what your body needs on a daily basis (including what you use during exercise), you can get by with consuming 40 percent or less of your calories from carbs. Eating more than that doesn’t necessarily benefit exercise because it’s not a case of “some is good, so more is better.” Most people who are training overeat carbs, given the limited amount and intensity of training that they do. (See the preceding section for more on proper carb loading before an event.)
Fully restoring muscle glycogen if you deplete any during exercise takes 24 to 48 hours, assuming you’re eating adequate amounts of carbs. If you’re on a low-carb regimen, the process takes longer, and you may be trying to do your next workout with less muscle and liver glycogen on board.
Despite what you may think, running low on carbs doesn’t automatically bump up your fat use during exercise. As everyone says in the exercise world, “Fat burns in a carbohydrate flame.” What that means is that if you don’t have carbs left in your muscles, you can’t use fat as a fuel very well either. Without glycogen, your fat use is compromised, and you have to slow down your pace to a level where you just don’t need much carbohydrate.
Do you need to restrict carbs so severely if you’re exercising regularly? Probably not. Even people with type 2 diabetes can handle carbs better when doing regular physical activity that depletes some muscle glycogen. You feel less tired and more energetic when eating some carbs during and after exercise to speed up muscle glycogen repletion.
Anyone with type 1 diabetes needs to keep blood glucose as near to normal as possible to get optimal glycogen into muscle and liver storage depots. It won’t be effectively restored if your blood glucose is running on the high side.
Taking in some carbs post-exercise is likely the most important time — particularly during that window of opportunity from 30 minutes to 2 hours after a workout when glycogen repletion rates are highest. That period is also when you need the least insulin to cover any carbs you eat.
Many different factors can impact your blood glucose responses, and the more you know about them, the better equipped you are to figure out what works best for you in almost every situation. This process always takes some trial and error.
Sometimes it’s still difficult to figure out what is causing the blood glucose or other exercise responses you’re having. Try these strategies if you’re experiencing any of these issues with being active with diabetes.
Getting low blood glucose during physical activity not only is annoying but also can compromise your ability to complete your event or competition. No one likes to get low during exercise.
If you’ve been experiencing any exercise-related lows, consider taking some of these actions or precautions to avoid it, especially if you use insulin:
If you’ve been experiencing high blood glucose related to being active, consider these possible ways to troubleshoot and correct your levels:
Did you ever DNF (“did not finish”) a race or a competition? Certainly, that can happen if you twist your ankle, cramp up, or otherwise get injured. But sometimes your performance is affected when you get tired too soon during an event or if the fatigue is so bad you simply can’t go on.
Here are actions you can take to prevent fatigue that comes on early or is bad enough to make you stop before you reach your athletic goals:
Has your exercise performance been less than you’d hoped recently? Many different things can cause poor performance or unusual fatigue, but here are some potential causes (and solutions) to consider when you have diabetes and are athletically inclined.
If you’re doing well with your workouts, but not with your races and events, you may simply not be resting long enough to restore glycogen, repair muscle damage (caused by every workout), and fully recover. Cutting back on your workouts (tapering) for at least one to two days before a big event is critical. During that time, keep your blood glucose as close to normal as possible so your glycogen levels are as full as possible for your race or event day.
Restoring your muscle glycogen between workouts takes eating enough carbohydrates and having insulin in your body that works adequately. Doing longer and harder workouts can deplete glycogen stores, and you may not be fully replenishing them fast enough because you’re either not eating enough carbs or not keeping your blood glucose in check. You must have an adequate amount of insulin available to restore the glycogen in your liver and muscles.
Having low iron body stores can cause you to feel tired all the time, colder than normal, and just generally lackluster. You can be iron deficient without having full-blown anemia. A simple blood test can check your hemoglobin (iron in red blood cells) and your overall iron status (serum ferritins). If your body’s iron levels are low for any reason (such as having dialysis), taking iron supplements can help; so can eating more red meat, which has the most absorbable form of iron.
Most adults with diabetes are magnesium deficient, especially when their blood glucose levels are higher than optimal, which causes more loss of magnesium through your urine. About 50 percent of the body’s magnesium supply is found in the bone; nearly another 50 percent is inside body tissue cells and organs, and less than 1 percent is in the blood. It’s a critical mineral because it impacts over 300 enzyme-controlled steps in metabolism, including protein synthesis, muscle and nerve function, immune function, blood pressure regulation, and blood glucose management.
Symptoms of low magnesium levels include agitation and anxiety, restless leg syndrome, sleep disorders, irritability, nausea and vomiting, abnormal heart rhythms, low blood pressure, confusion, muscle spasm and weakness, hyperventilation, insomnia, poor nail growth, and even seizures. Having a magnesium deficiency likely compromises your blood glucose and exercise, and you may even experience some muscle cramping (unrelated to dehydration). Low magnesium can also lead to potassium imbalances.
Refining and overprocessing foods causes a loss of almost all the magnesium found in those foods originally, and the abundance of these foods leads to a widespread magnesium deficiency even in people without diabetes. You can eat more foods with magnesium in them naturally — such as nuts and seeds (especially almonds), dark leafy greens, legumes (like black beans), soymilk, yogurt, oats, avocados, fish, and even dark chocolate. However, taking a supplement may also help correct deficiencies in your diet. (Magnesium in the aspartate, citrate, lactate, and chloride forms is absorbed better than magnesium oxide and sulfate.)
With diabetes, thiamin (vitamin B1) deficiency is also a likely culprit affecting your athletic performance, particularly if you’re not eating a healthful diet. The eight vitamins in the B family are integrally involved in metabolism and even red blood cell formation. People who take metformin to control diabetes may end up deficient in vitamins B6 and B12, both of which are essential for proper nerve function and muscle contractions. Thiamin (B1) is depleted by alcohol intake, birth control pill use, and more. Taking a generic B complex vitamin daily can help you avoid these issues, and excesses of most B vitamins are harmless (and simply peed out).
Insulin pumps can help manage blood glucose and deliver rapid-acting insulin analogs like Humalog, Novolog, Apidra, and Fiasp. The body metabolizes these altered insulins differently than it does long-acting Lantus/Basaglar.
The rapid-acting insulins have little to no insulin-like growth factor (IGF) affinity, and most adults are reliant on IGF rather than human growth hormone (which is only higher in youth) to stimulate muscle growth and repair. Lantus and Basaglar stimulate IGF activity, so you may want to talk with your doctor about combining insulin pump use (for meal boluses) with basal insulin injections to get more IGF activity to promote muscle repair between workouts.
Many people with diabetes also have thyroid hormone imbalances. Having lower levels of functioning T3 and T4 hormones can cause early fatigue and poor exercise performance, among other things. However, just checking your main thyroid hormones (TSH, T3, and T4) may not be enough. You may also want to consider getting your thyroid antibodies checked if your thyroid hormones levels are normal and nothing else is helping your exercise training. Specifically check for antibodies to thyroid peroxidase, especially if you have diagnosed celiac disease.
If you’ve been through all the confounding factors in the preceding sections and had everything check out okay, consider other possible issues. The fix may be as simple as monitoring your hydration status (and staying better hydrated, especially when your blood glucose runs higher). Or you may need to bump up your daily carbohydrate intake; adding even just 50 grams per day to your diet may help. Check for other possible vitamin and mineral deficiencies (vitamin D, potassium, and so on). If you use statins to lower your cholesterol, be aware that some statins cause unexplained muscle fatigue, so you may need to talk with your doctor about trying a different one. Your performance can also be impacted by frequent hypoglycemia or hypoglycemia-associated autonomic failure (see Chapter 4 for a discussion of that issue).
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