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Experiencing dizziness after 20 miles; the merits of zero-drop running shoes; the usefulness of recovery runs
Dizzy After 20
I have done several 50K runs, but even during training, I start to feel like I have vertigo after about 20 miles. I don’t feel excessively fatigued but, rather, dizzy. I’ve been told that this is a fueling issue and that I need more protein. I’m a vegetarian, but very conscious of my protein intake. What causes the dizziness?
—Rebecca Dusseau, Eugene, OR
Such a sensation is common among ultrarunners. Low consumption of protein isn’t a likely factor, though. However, being a vegetarian means a B12 deficiency is possible. According to Benjamin R. Lewis, M.D. from the University of Utah, “If Rebecca is anemic, a consequence of B12 deficiency, she’ll certainly feel light-headed and fatigued.” To combat this, add some B12 to your diet; vegetarian sources are few, but try kombucha and nutritional yeast.
Dr. Lewis says your issue is “most likely hypoglycemia, since your symptoms don’t start until you pass 20 miles. You’re probably transitioning to burning fats right around that time.” Hypoglycemia is a condition caused by a drop in blood sugar (glucose), and a large drop can cause a per- son to slip into a coma or go into cardiac arrest.
Dr. Lewis suggests three main fixes for hypoglycemia: “Become better at burning fats, store more liver and muscle glycogen and eat smarter on the run.” Your body gets its energy from three sources: ingested carbohydrates (e.g. gels); intramuscular and liver carbohydrate stores (glycogen); intramuscular and adipose fat stores (badonkadonk or “spare tire”). At rest an elite endurance athlete typically metabolizes less than 40 percent of their energy from carbohydrate. Due to an ultrarunner employing a comparatively slow pace and lower intensity, fat stores become the preferred energy source.
There are two well-accepted techniques to becoming more fat adapted. During the base training phase, employ a low-carbohydrate diet and spend the majority of your training time doing easy, steady-state efforts. The second way is to train in a glycogen-depleted state, which forces your body to use its fat stores as fuel. The easiest way to do this is running first thing in the morning, before you eat, to assure your glycogen levels are low.
Your issue could also be just getting behind on caloric consumption. Try to eat a gel (or other preferred carbohydrate source of about 100 calories) every 20 to 30 minutes and see if that fixes the issue.
Because training depletes glycogen stores, replenish them right away (within 30 minutes post-run) to train your body to store more on- board energy.
Considering the Big Zero (Drop)
I have calf problems and chronic Achilles tendonitis and I’ve heard transitioning into zero-drop running shoes can help. Fact or wishful thinking?
—Gerald Madler, Columbus, GA
Chronic Achilles tendonitis is an inflammatory condition caused by trauma or overuse to the largest tendon in the body. Relief requires allowing the micro-tears to heal and inflammation to reduce, which means … time off—the remedy no runner wants to hear.
Says Dr. Ray McClanahan, sports podiatrist and founder of Northwest Foot & Ankle, “Zero- drop shoes can be helpful in restoring Achilles tendon and calf health, but should be used appropriately and in combination with a proper training plan, including gradual changes in both training volume and intensity.” I usually transition my clients with progressive barefoot walking and grass sprints. The goal is to build strong, healthy and injury-resistant lower legs.
Using footwear with an extreme differential between heel and toe (like 14mm) may actually shorten your Achilles tendon. Although rapidly changing, this design still encompasses most conventional shoes on the market.
Recovering on the Run?
My understanding is that a recovery run is an easy run the day after a serious training effort. Is there really a benefit to running as recovery, or is it better to do a non-running activity such as cycling? Is a recovery run just a way to keep your weekly mileage up, or is there more to it than that?
—Ian Rodrigues, Bradford, ONT
Since athletes vary greatly in genetics, physiology and athletic history, a one-size-fits- all approach to recovery is difficult to prescribe. For example an athlete who is at the end of peak week might be teetering on becoming injured; a recovery run could push him over the brink. Another runner who is in the early stages of a training program and has years of experience might feel great after a hard effort, having caused no significant structural damage. The former might need either a whole day off or a recovery bike ride. The latter can probably benefit from a recovery run.
I like to have trail runners reduce the pounding by occasionally spinning easy on a bike or swimming for active recovery sessions. These athletes are of varying ability, but are usually pushing the upper limits of their run volume. The goal is to get blood flowing to your muscles (to quicken recovery), but not put more trauma on your tendons and joints.
Coach Hal Higdon, author of 34 books, including the best-selling Marathon: The Ultimate Training Guide, takes an antagonistic view of cross training for recovery, however, saying, “You may convert what should be an ‘easy’ day to a ‘hard’ day by using different muscles and miss the benefit you get from resting your body to get it ready for the next hard running workout.” If you are nailing all your important workouts through the week, don’t stress out on your recovery run. Listening to your body and knowing when it can handle one, and when it can’t, is the key.