Bounteous tidings dear readers on this titillating Tuesday. I’m not sure what the weather is like where you are, but it has been a SCORCHER in Seattle this week.
Yesterday evening’s thunderstorm was a welcome respite from the oppressive heat and humidity for us city slickers in Seattle. However, the lightning set 51 new wildfires aflame in Oregon, and at least one new fire near Olympia in Washington. My heart goes out to the people displaced from their homes, and to the firefighters continuing to battle blazes across the Northwest. I will spare everybody another rant about climate change. However, if current trends continue we can expect to see more hot, dry summers, extreme weather events, and wildfires.
OK- I’ll step off of my soapbox, for the time being (besides, there are much more eloquent scribes than I addressing the issue: check out Timothy Egan’s take, over at the Times). This morning I braved the blistering heat for a challenging tempo run.
A tempo run is deceptively simple: you run for an extended period of time at a “comfortably hard” pace. While comfortably hard may sound oxymoronic, you’re shooting for an effort that is challenging, yet sustainable. You should be struggling, but not so much that your eyes are bleeding. There are many metrics to figuring out how fast that should be (Runner’s World, as always, has a great article on tempo training). The easiest way to undertake a tempo run is the “Talk-Test.” You should be working hard enough that you can’t complete a sentence, but not so hard that you can’t even spit out a single word. For me, my tempo workout looked like this:
The point of a tempo run is to increase your lactate threshold. When your muscles are working hard, they burn a lot of energy, in the form of a fantastic little molecule called ATP. Cells make ATP using glucose. We as endurance athletes burn a lot of glucose, and thus pretty much need to be oozing carbohydrates from our pores at all times.
Your cells’ favorite way to make ATP is by a process called oxidative phosphorylation, using the electron transport chain and the TCA cycle. Oxidative phosphorylation gets a lot of bang for its buck: 32 molecules of energy-giving ATP per glucose burned.
Oxidative phosphorylation, as its name suggests, requires a lot of oxygen. When your muscles are working hard your blood can’t deliver oxygen to the cells fast enough, causing anaerobic conditions. Luckily, there’s a back-up plan in place: your muscles also can make ATP by a process called fermentation.
Fermentation is less efficient (a paltry 2 molecules of ATP per glucose), but it keeps your muscle fibers firing when times get tough. In addition to being inefficient, fermentation produces lactic acid as a byproduct.
Lactic acid is NOT what makes you sore after a tough workout. Your gym teacher lied to you about that one. Your cells are able to clear lactic acid and even use it as an energy source under normal circumstances. However, when lactic acid builds up faster than it can be cleared away, your body begins to get nervous and starts putting in place mechanisms to protect itself. This is called the “lactate threshold.”
A lactic acid build-up in the blood indicates that your muscles are burning through glucose like it’s going out of style. Our other organ that needs a constant glucose fix is the big Homo sapiens brain. Your brain is a glucose JUNKIE. In order to protect its stash, the brain will send signals to your muscles to tell them to simmer down and stop working if it thinks that they are getting glucose-greedy. This manifests as fatigue in the muscles themselves.
The circuits leading to muscle fatigue are there for a good reason: to prevent you from literally exercising until you die. However, your brain is SO fiercely protective of its glucose reserves, it likes to send the fatigue signal to your muscles cells FAR before there is any danger of running out of fuel. The lactate threshold is higher than it needs to be.
Tempo workouts have you performing at the lactate threshold for an extended period of time. Forcing your muscles to keep firing, even as the brain senses lactic acid and is sending messages to the cells to STOP, has two benefits.
First: Tempo workouts teach your muscles to effectively use lactate as a fuel source, clearing it from the bloodstream. This alters the physiological lactate threshold: reducing the rate of build up in subsequent workouts, letting you push harder for longer.
Second: Tempo workouts prove to your brain that you can keep exercising YOU WILL NOT DIE even when lactate levels are high. This alters the psychological aspect of the lactate threshold: getting your junkie brain to simmer down and stop sending fatigue signals at the first sign of strenuous effort. Training your brain is just as important as training your body.
Tempo workouts are hard, and they are hard for an extended period of time, but they make you a better runner (or cyclist, or swimmer, or whatever). Nobody likes to feel uncomfortable, but pushing yourself beyond your comfort zone is the only way to make progress.
One of my favorite running bloggers, stuftmama, recently shared the brilliantly simple mantra: Make yourself do hard things. I gotta admit, every time I do a tempo workout, I have to tell myself these very words when I’m tempted to slack on the pace.
Tempo workouts are hard, but they are effective and that makes them great! Check out some of those links!
HAVE a SUPER Tuesday. Train hard. Have fun.