When life puts obstacles in your path to fitness, is it better to push through or ease up?

When you’re not exactly looking forward to a run, your brain can come up with thousands of absurd excuses. We’ve all been there: It’s going to get dark soon! This comforter has never felt cozier! My cat might be lonely if I leave her alone at home! On the other hand, sometimes your body really does need an off day or two.

So how can you tell the difference between self-induced BS-ing and a legitimate reason to rest? Tom Kloos, coach of the Bay Area Track Club and Saint Mary’s College of California, provides this rule of thumb: “If you don’t work with a coach, imagine if you did and have an imaginary conversation with that person. If you’re embarrassed by your reasoning, you know you should do the workout.” He adds that it’s best to consider the forest (your training) rather than the tree (one run). A single workout isn’t that important, but you don’t want to look out and see a barren forest. Use this field guide to navigate the woods.

3 Times When You May Need To Consider A Day Off

OBSTACLE: Fatigue
WHAT TO DO: SLOW
Did you accidentally watch an entire season of “Sherlock” last night and it’s all you can do to keep your eyes open? Lace up, run 1 mile and see how you feel. Hillary Kigar, San Francisco–based high school coach and WR columnist says, “A lot of times, the first little bit is when you feel really tired, but once you get going, you’re fine.” If you are still dragging 10 minutes in, head home and take a nap. Kigar adds that if you have a few of these super-sleepy days in a row, take some time off running to level set.

Related: Should You Run Or Take A Day Off

headache

OBSTACLE: Headache
WHAT TO DO: STOP
Unless we’re talking very mild discomfort, running will likely aggravate the ache. It’s possible your pain is a symptom of dehydration, so you can drink some water and see how you feel in a few hours. “It’s often a sign that you’re on the verge of getting sick,” says Kloos, who says that stressing the body further by running could push you over the edge.

aches and pains

OBSTACLE: Aches And Pains
WHAT TO DO: SLOW
This is a tricky one. Achy muscles can mean you’re training hard and getting stronger—or that you’re on the brink of injury. Kloos uses this three-day plan to decipher normal soreness from entry to the danger zone. The first day you feel an ache, ignore it—it’s probably nothing. The second day, self-treat: “Add extra time stretching, using a stick massage or icing it after your run.” The third day, “Use aggressive action.” This means something is likely wrong. Take time off until the pain subsides.

Related: Should You Run Through Pain