What does a typical low feel like?

Typical symptoms of hypoglycemia (Figure 5-1) include shakiness, hand trembling, tingling of your hands or tongue, sweating, mental confusion, irritability, poor physical coordination (that is, clumsiness), and vision changes. Your usual symptoms can vary with your training state, diet, environmental conditions, and more, which is why knowing all the possible symptoms is helpful. Plus, knowing the symptoms means you can treat a low quickly.

Look for signs of any of these typical symptoms of hypoglycemia:

• Cold or clammy skin
• Dizziness or lightheadedness
• Double or blurred vision
• Elevated pulse rate (beyond exercise-induced increases)
• Headache
• Inability to do basic math
• Insomnia
• Irritability
• Mental confusion
• Nausea
• Nightmares
• Poor physical coordination
• Rapid-onset fatigue (sudden, unusual, or unexpected tiredness)
• Shakiness in your hands
• Sweating
• Tingling of hands or tongue
• Visual spots
• Weakness

How can you tell if you’re low?

You can’t always easily tell right away if your blood glucose is too high or low when you start feeling funny, especially during exercise. When your blood glucose is changing rapidly, you often can’t tell which direction it’s going.

In those cases, use your blood glucose meter to check. You can wait until your symptoms progress, but the full-blown symptoms of a low are never fun; checking with a meter if you can may allow you to treat symptoms sooner and avoid feeling worse. Using a continuous glucose monitor may be helpful as well in identifying a trend toward low blood glucose.

If you’ve ever experienced hypoglycemia, you may be familiar with the effect that it can have on your ability to think straight and act normal. If you ever find yourself thinking, “I know what 2 + 2 equals, but I just can’t figure it out right now,” you’re probably low. If you try for several minutes to program your clock radio with the TV remote, you’re also likely experiencing a lack of glucose needed for normal brain function.

Feeling shaky, extremely fatigued all of a sudden, or weak may be symptoms of a low that’s affecting your whole body and not just how well you think.

Always be prepared to treat hypoglycemia

If you’re an insulin user and have ever been caught somewhere without having anything with you to treat hypoglycemia, you’re not likely to forget to bring supplies along the next time. Carry some glucose or other carbohydrates with you whenever you’re exercising, even if you’re just out walking the dog.

Even if you’ve never experienced a low before, keep supplies on hand to treat it just in case. You’d hate to be unprepared for your first time.

Check your blood glucose

Keep a blood glucose meter handy to check your blood glucose regularly. Check immediately after exercise and then every 30 to 60 minutes for a couple of hours to determine what kind of lasting effect the exercise is having. If you experience symptoms and have your blood glucose meter handy, confirm that you’re having a low. If you don’t have a meter, go ahead and treat for hypoglycemia anyway (by eating rapidly absorbed carbohydrates) to be on the safe side.

Treat lows with carbohydrate

Any carbohydrate you take in during and after exercise to prevent or treat hypoglycemia should have a higher glycemic index (GI) value for rapid absorption. That means that the carbohydrate gets into your system quickly. In most circumstances, don’t eat things that also have a high fat content — such as chocolate candy, donuts, or potato chips — because the fat in those foods slows down how quickly your body digests the carbohydrates. (Refer to the following section for more on picking the right foods for treating hypoglycemia.)

Treat low blood glucose immediately with small amounts (4 to 15 grams) of high-GI carbohydrates, wait 5 to 10 minutes for them to take effect, and then recheck your glucose levels or monitor your symptoms. Consume the same amount of carbohydrate again only if your hypoglycemic symptoms haven’t started to resolve by then.

Your whole body usually only has about 5 grams of glucose total in your bloodstream, so avoid eating too much, or you’ll likely end up with elevated glucose levels later. Unless the insulin levels in your body are high, you may only need anywhere from 4 to 15 grams of glucose to raise your blood glucose to normal.

Choose the carbohydrates that work the fastest

The fastest treatments contain straight glucose (also called dextrose). You can find straight glucose in glucose tablets, glucose gels, Gu, most sports drinks, candies like Smarties and SweeTARTS, and more.

Glucose tablets, gels, or liquids have a couple of benefits for treating lows because glucose is the sugar that is normally in the blood, and it gets there most rapidly after you eat or drink it. These products also come in measured amounts — usually 4 grams per tablet or 15 grams per gel or liquid container — making it easy to consume only a specific amount. With trial and error, you can determine how much each tablet, gel, or liquid is likely to raise your blood glucose.

Using glucose tablets — with 4 grams of glucose per tablet — is an effective way to treat and prevent lows without overshooting on carbohydrates (and ending up high) or calories (which can make you gain weight; see the sidebar “Treating lows without gaining extra fat weight” in this chapter).

You may not always have glucose handy to treat hypoglycemia, though, and you can use other foods and drinks as well. Always carry treatments with you in case of emergency:

• One to two rolls of Smarties (6 grams each)
• One to two pieces of hard or sugary candy (but not chocolate)
• Four ounces of regular soda
• Eight ounces of juice diluted to be half water (to speed up digestion)
• Eight ounces of sports drink (6 to 9 grams of carbohydrate)
• Eight ounces of skim milk
• Two to three graham crackers or six saltine crackers

The white sugar (sucrose) in regular sodas and candy also works as a treatment because it’s half glucose. You can also use skim milk, hard candies, bagels, bread, crackers, cornflakes, and white potatoes.

Avoid fruit juice as your first choice to treat lows because its primary sugar (fructose) has a relatively low rate of being converted into glucose, and the body absorbs it more slowly. Although juice has traditionally been used for treatment, it may lead to overtreatment of lows while you’re waiting for its effects to kick in. Some juices have added glucose, though, and don’t contain just fructose, so they may work faster.

Never treat hypoglycemia with low-GI carbohydrates (such as legumes) because the body doesn’t absorb them rapidly enough to treat lows quickly. In the preceding section, I note that you shouldn’t use chocolate and other high-fat sugary foods to treat hypoglycemia because of their slow absorption rate, and that’s generally true. However, how much and what you treat hypoglycemia with may vary by the situation. If you’re likely to keep dropping from the insulin in your system or for another reason, you may need to consume additional food or drinks with greater staying power — that is, with some fat or protein to go with the carbohydrate, like peanut butter crackers or energy bars.

Milk is a good treatment option because it contains 7 to 8 grams of protein, along with some fat depending on the type. For prevention of lows that come on later after exercise, whole milk is much more effective than skim milk or even sports drinks, likely because of the extra fat in the whole variety that takes longer to fully digest and impact your blood glucose.

Chocolate milk is a balanced and effective recovery drink for prevention of lows and recovery from exercise. If you can’t drink milk, try soymilk or other options with a mostly equal mix of carbohydrate, protein, and fat.

Keep glucagon on hand for bad lows

Having a glucagon kit on hand may also be beneficial if you experience a bad low that lasts a long time or that you’re unable to treat yourself. Of course, your family and friends will need to learn how to use it on you. Glucagon could previously only be given as an injection, but a nasal glucagon spray is in the works. Other companies are working on making more stable formulations to be given as mini-doses with a glucagon pen (similar to the idea of using an insulin pen) to raise blood glucose without taking in glucose or food.

Prevent hypoglycemia after exercise

As I mention earlier in the chapter, after-exercise lows can occur both because your muscle carbohydrates (glycogen) are low and being replenished (during which time your insulin action is higher) and because your response of glucose-raising hormones after you’ve recently exercised may be diminished.

If you use insulin or take oral medications that cause insulin release, you need to be on the offensive to prevent getting low in the hours after exercise.

The period in the first 30 minutes to 2 hours after exercise is the critical time when your muscles can take up glucose without much need for insulin. If you can start to restore your muscle glycogen right after exercise at the fastest rate by taking in adequate carbohydrates during this window of opportunity, you’re less likely to get as low later. Eating a low-carbohydrate diet during this time not only slows down the rate of glycogen that is being replaced but also sets you up for delayed hypoglycemia if you use insulin.

If you don’t use insulin, eating fewer carbohydrates during the first 30 minutes to 2 hours after exercise may keep your insulin action high for longer.

You may have more than one time following a workout when your body rapidly depletes your blood glucose. One study showed a biphasic increase in carbohydrate requirements — meaning that you can get low at two different times, both right after exercise and again from 7 to 11 hours afterward. Although this effect may not happen in everyone, you should still be on the alert for this second wave of potential hypoglycemia after exercise so you can prevent it.

Although carbohydrate is most important to replace in the short run, for longer prevention of lows without first causing short-term hyperglycemia, extra protein and fat intake will also help because they have more staying power.

Regularly restore muscle glycogen to lower risk

If you do exercise training on a regular basis, you need to take in enough carbohydrate every day to restore your muscle and liver glycogen between workouts. When you have diabetes, you must manage your blood glucose before and after exercise so that you can put carbohydrate back into those storage places normally.

To restore glycogen effectively, you need adequate insulin, especially more than an hour after exercise when glucose uptake is more dependent on insulin.

Taking in some carbohydrate immediately after you finish a workout or race will speed up your initial glycogen replacement and help lower your risk of developing low blood glucose later, and your body won’t need much insulin then to accomplish that. Adequate carbohydrate intake also helps ensure that your glycogen stores are maximally loaded by the time your next workout rolls around.

Full muscle glycogen replacement after exercise can take 24 to 48 hours, so that is when your blood glucose needs to stay as close to normal as possible.

If you eat a low-carbohydrate diet, fully restoring your glycogen takes longer. For that reason, you may want to take in at least 130 grams of carbohydrate per day in your diet on days you exercise. Also, make sure you take enough insulin (if you use it) to get those carbohydrates properly stored in your muscles and liver.

Consider loading with carbohydrates

If you’re going to run a half-marathon or a marathon, you need to carbohydrate load to make sure your glycogen stores are full at the start of the race. Keep these points in mind for effective carbohydrate loading when you have diabetes or prediabetes:

• You don’t need to spend a week, or even as long as three days, overconsuming carbohydrate to load up your muscle glycogen. Even a single day with a higher carbohydrate intake and rest or tapering can effectively maximize carbohydrate stores in muscles.
• Eating as much carbohydrate as the typical glycogen-loading scenarios recommend may be counterproductive for most people with diabetes. Your carbohydrate intake doesn’t need to exceed 50 percent of your calories on the day that you load, assuming you eat enough calories to keep your weight stable with all your exercise training.
• For carbohydrate loading to be effective with diabetes, your muscles must be able to take up enough glucose.
• Make sure you have sufficient insulin when you take in carbohydrate to prevent hyperglycemia and promote muscle glucose uptake.
• Consuming higher-fiber carbohydrate sources will prevent an excessive rise in your blood glucose and still be effective for loading, but it may cause bloating and discomfort if consumed too close to your activity.
• To optimize your liver glycogen stores, keeping your blood glucose at closer to normal is the most effective strategy.

To maximize your glycogen stores, combine rest, a carbohydrate-rich diet, and good blood glucose management for a single day.

Beware of hypoglycemia unawareness

Some people develop hypoglycemia unawareness, which means they either don’t have or fail to recognize the usual symptoms of getting low. This condition appears to be more common if you keep your blood glucose in a tight normal range or you have frequent lows already.

Most people who have had type 1 diabetes for longer than 10 years have a blunted release of glucose-raising hormones (for example, glucagon and adrenaline) when they get low from having too much insulin in their bodies.

If you ever get a bad low without being aware of it, you may have this condition, which is estimated to affect up to 20 percent of insulin users. Although it’s less common in people with type 2 diabetes, those who have both hypoglycemia unawareness and type 2 diabetes have a greater likelihood of experiencing a severe low and a decline in thinking ability.

Why does this condition happen? Normally, when your blood glucose starts to get too low, you experience symptoms such as sweating, shaking, weakness, and vision changes, due to the release of adrenaline and the other glucose-raising hormones. If you’re unaware, though, you may have milder or missing symptoms due to a blunted release of these hormones in response to dropping blood glucose levels. (Check out the earlier section “What does a typical low feel like?” for a fuller list of hypoglycemia symptoms.)

Because low blood glucose affects your ability to think and reason, you may even test your blood glucose when you’re low and not realize that the numbers you’re seeing mean you need to eat. Some people resist help treating it from others or run away from paramedics who are trying to help them. In other words, the low prevents you from thinking straight and doing things to raise your blood glucose. Given that the nerves use blood glucose as a fuel, this effect isn’t entirely surprising — but it certainly is alarming.

Though you can easily treat mild hypoglycemia with carbohydrate intake, if your blood glucose drops too low without symptoms or enough time to react and treat it, you may be become unresponsive or unconscious.

If you’re experiencing hypoglycemia unawareness, consider trying one of these options:

• Prevent all hypoglycemia for two to three weeks straight to regain some level of awareness. Set a target blood glucose of 150 mg/dL during that time.
• Wear a continuous glucose monitoring (CGM) device to alert you to decreases in your blood glucose before they get to a critically low point.

Find out more about HAAF

Many insulin users also experience a condition known as hypoglycemia-associate autonomic failure (HAAF), but it’s most likely to happen if you have type 1 diabetes and not so much for anyone with type 2. This condition involves an abnormal hormonal response to either exercise or hypoglycemia, but it is most likely to occur when you’ve exercised within the past 24 hours or you had a bad low during that time frame.

If you’ve had a bad low in the prior 24 hours or exercised during that time, you may be more prone to developing hypoglycemia the next time you exercise.

Because having diabetes for longer than 10 years often results in a blunted release of glucose-raising hormones when you get low, your body may release less of these hormones than it used to, and your blood glucose may stay or go lower than before. However, women’s hormonal responses appear to be better preserved during exercise after either prior exercise or a low compared with men’s, making the fairer sex better able to respond to exercise-induced lows.

How low you go and how long you stay low also affect whether you experience HAAF during your next hypoglycemia event. For example, short duration hypoglycemia has less of a lasting effect on your ability to respond the next time compared to longer lows, so detecting and treating hypoglycemia early can help prevent this condition.

In one study, participants underwent different levels of induced hypoglycemia for two hours: 70 mg/dL, 60 mg/dL, and 50 mg/dL. When their glucose levels had been normal the previous day, they had perfect hormonal responses to exercise the next day, but any hypoglycemia, even just down to 70 mg/dL, blunted their glucose-raising hormonal responses during their next workout. And the lower it had gone, the worse those next-workout responses were.

You’re more likely to develop bad lows within 24 to 48 hours after a day when you exercised more than usual or with greater intensity (such as changing a training schedule or doing a competition). This effect appears to occur rapidly — within a couple of hours — and can increase your risk of getting low for the rest of the day after a workout and the next day.

Effects of sprinting

Doing a 10-second sprint either before or immediately after a moderate-intensity workout keeps your blood glucose more stable for at least two hours afterward. This technique works anytime during exercise, but it doesn’t reduce the amount of carbohydrate needed to prevent lows during the eight hours following such a sprint.

Sprinting to raise your blood glucose to prevent a low doesn’t work if you have a lot of insulin in your bloodstream or experience a blunted hormonal response to activity. The good news is that having a prior low won’t affect your release of glucose-raising hormones when you do a short sprint.

You can also keep blood glucose higher during exercise by interspersing four-second sprints into an easier workout every two minutes or so (sort of like doing interval training of sorts). These effects are due to a greater glucose release by the liver during intense exercise and less glucose uptake by muscles during exercise and recovery.

Sprints work best when you have a limited amount of insulin in your system and may not prevent hypoglycemia when you have a lot of insulin on board. When the short-term hormonal effects wear off, however, you can develop hypoglycemia later because doing sprints uses up more muscle glycogen.

Variation in the order of training

Another strategy to manage or prevent lows during activities is to change the order of exercises you do, when your choices are either aerobic or resistance training. Blood glucose levels tend to fall more during moderate aerobic exercise and less afterward compared to resistance workouts, which causes less of a decline during the activity and more overnight.

Aerobic and resistance activities done during the same workout can be ordered strategically to better manage your blood glucose:

• If you start out on the low side, do resistance training first, followed by aerobic work, to keep glucose higher throughout the first half of your workout.
• If starting out on the high side with your blood glucose, begin with aerobic training first (assuming it’s moderate) to lower blood glucose levels and follow it up with resistance work, during which it will stay more stable.