In part two of resident diabetic Henry Stewart's ongoing series, Insulin is Not a Cure, he explained the best-case scenario when taking insulin (exhaustion), the worst (death), and the normal (really bad).

Insulin therapy is all guesswork. As Sam Whiting wrote in the San Francisco Gate, the idea that diabetics can control their blood-sugar levels is a myth: the best for which they can hope is to influence them. A diabetic, essentially, is trying to be his pancreas, which is about as feasible as him trying to do the work of his heart or lungs. A properly functioning body knows its blood glucose levels and administers small amounts of insulin whenever necessary. A diabetic can only prick his finger to check his blood so many times a day, take so many injections, make so many guesses as to how whatever he’s planned to do and eat that day will affect his condition. (Some diabetics now have “insulin pumps,” a continuously worn needle connected to a small gizmo that allows many small insulin infusions throughout the day, more accurately mimicking a pancreas.) He can overdose by accident. And once the insulin has entered the bloodstream, there’s no way to get it out, like an egg in a cake. All you can do is eat. The insulin isn’t just feeding you; you’re feeding it.

But food isn’t the only factor to influence blood sugar, and even it does so in peculiar, often unpredictable ways; you could eat the same thing for breakfast and inject the same amount of insulin on two different days and wind up with radically different sugar-readings by lunch. Though peanuts are essentially free of the kind of carbs that would raise your blood sugar, they can have that effect because of the way fat affects insulin reception. Alcohol usually lowers blood sugar levels, counterintuitively, as do some teas. (Sometimes, though, they don’t, even though they have several times in the past, and you wake up in the morning with a blood sugar reading much higher than you anticipated!) Stress affects blood sugar levels, as does physical activity. Maybe you fall asleep right after dinner, and because of inactivity the insulin never really gets worked through your system. Maybe an area of the body has become so damaged from repeated injections that the insulin doesn’t properly make it into the bloodstream.

Diabetics have to monitor themselves closely, discover patterns in the ways certain foods and activities affect them, and use that information to make educated guesses as to how much insulin to inject, what to eat and how much of it, how much exercise to perform. If a diabetic takes insulin and fails to eat, or fails to eat enough, or fails to eat soon enough (which is why I collapsed that time in the middle of dinner—it took ten or fifteen minutes longer to cook than I had supposed), they can at worst suffer brain damage or slip into a coma. At best, they get dizzy and disoriented, like a sudden onset of drunkenness without any of the fun.

Healthy blood sugar levels fall within a range of 70-110 [mg of glucose per dL of blood]. (Diabetics hope to keep their sugars within that range, or close to it, but it’s impossible to be consistent.) Once levels begin to fall below 70, the symptoms of hypoglycemia begin. At first, it might just be a mild sluggishness, a difficulty concentrating. The brain is hungry. But if blood sugar levels continue to fall, the physical response escalates: sometimes gradually, sometimes all at once, the brain surpasses hunger—it’s starving, at which point you might start sweating as your body temperature rises; severe disorientation ensues.

It’s surprisingly simple to get out of a hypoglycemic episode: just eat some sugar. A good diabetic always carries a packet of Skittles, a can of Coke or a tube of glucose tablets for just such an emergency. But in truth you need two things to pull yourself out of hypoglycemia: one is sugar; the other, rational thinking—and that’s the one thing a hypoglycemic diabetic definitely lacks.

Recently, after changing insulins and adjusting my regiment, I was having trouble controlling my sugar: it was way too high before dinner and way too high when I woke up, even if I took significantly more insulin than usual at dinner and exercised rigorously afterwards. Really, it just takes time for the body to adjust to a new insulin and a new routine, but I was frustrated.

One day, I spend nearly 24 hours hovering near 200, more than twice a normal reading, and am fed up. Before lunch, I'm at 166, and decide to shoot seven units of insulin into my arm instead of the usual five or six. I also decide to eat a tub of "Spicy PowerFu Salad" for lunch instead of a "Spicy PowerFu Salad Sandwich," because I feel the carbs in a whole-wheat pita are now something to which I can only treat myself as a reward for good readings. Worried that a sedentary desk job isn't helping my sugar levels either, I also decide to take a healthy walk after lunch. I get two blocks away from The L’s offices, down Jay Street in DUMBO, when it feels like I stepped in dog shit. I take a look behind me but don’t see anything unusual. Maybe the sidewalk turns to mush in front of Pedro's? I make a mental note to check on my way back.

But then it happens again a block later, and then again a few steps after that, and I realize it isn't the ground that's gone soft—it's my knees. Soon, I look like I'm futterwacking as I try to walk: my legs splaying out involuntarily, my knees trembling, like a toddler taking its first steps. I make it almost two blocks like this, until I'm standing in the shadow of the office, and I have to stop and cling to a nearby staircase’s railing, lest I collapse. Misting rain brushes my face like water from a showerhead. I must look drunk, I think. Diabetics are often confused for drunks.

Because my brain's not working, I tell myself, "pull yourself together!" instead of, say, chewing up a few of the glucose tablets knocking around in my pocket. After a few moments I futterwack to the building's main entrance and wait for an elevator. I always use the side entrance and climb the stairs, but I have enough sense not to overexert myself. Exertion is making it worse. Once I make it to the office door, I stumble through and fall roughly into a sitting position onto the boxes of back issues near the front door. With my back to the intern at the front desk, I pop a glucose tablet, hoping it'll stop the tremors in my legs, and start reading, not realizing that I'm sniffling from the rain.

In a moment, I feel a hand on my back. "Are you OK?" the intern asks sweetly, like a nurse. I force an easy smile; that I can do so must mean I am, that I'm re-sugared. "Yes," I say, "thank you."

"Oh, OK!" she says with relief. "I thought you were crying!"

That would be a few days later, when I weep uncontrollably in bed for nearly an hour before I think to check my blood sugar and discover it’s severely low—about 25—which would account for why I had suddenly lost my mind. I had given myself a slightly larger shot of insulin that evening because I was planning to break my strict diet by eating three sugar-free cookies for dessert. (They are made with white flour, which is essentially sugar, as far as my metabolism is concerned.) Just to be careful, I also rode my roommate’s stationary bike for 15 minutes—some form of activity, even just washing the dishes, usually helps insulin to do its job—and drank a mug of a tea meant to lower blood sugar levels (which it actually does, thanks to some magical natural compound). Turns out I had been overly vigilant.

Of course, a diabetic could be conservative about his insulin shots and intentionally keep his blood sugar high. And, in fact, this is what many in the medical community recommend; doctors are more concerned with the short-term dangers than the long. My doctor is happy if I keep my blood sugar at or below 200, even though a reading of, say, 185 would be roughly double a normal level. Chronic high blood sugars—though there’s some small disagreement about when high becomes too high—are responsible for the disease’s terrifying, long-term side effects, which afflict many diabetics later in life: amputated limbs, failed kidneys, blindness. Because of these threats, I’m paranoid about playing it safe. But, at a certain point, being cautious becomes putting myself at risk.

The fourth and final installment, in which Henry discusses health insurance, car crashes and antiquated medicine, appears tomorrow.