It’s marathon season, and there’s nothing more essential to an endurance training program than the long run.

Not only does it strengthen the heart and lungs by boosting the flow of blood and oxygen, but it also improves muscle endurance, primes your body to burn fuel more efficiently and provides that boost in confidence to mentally tackle the mounting mileage.

But there’s also a dark side to the long run that strikes fear in the hearts of many runners.

Whether it’s a nasty case of gastrointestinal distress, “bonking” (hitting the proverbial wall) too early or overtraining to the point of injury, it’s important to keep a few things in mind to help your long runs help you in the long run.

BEFORE the run…

1. Fueling incorrectly. 

Runners’ nutritional needs and tolerance may vary, but aim for 30-60 grams of carbohydrates per hour of activity, and keep it simple with low-sugar foods and drinks that you know agree with your system. (Learn from my recent mishaps during my own marathon training here)

2. Avoiding the warm-up.

A solid 10-minute warm-up slowly raises heart rate, dilates blood vessels and raises core temperature, ensuring that your muscles are flexible, operating efficiently and are well supplied with oxygen.

DURING the run…

3. Going too far.

It’s easy to get carried away and bite off more than you can chew, mileage-wise, but err on the conservative side by following a plan that takes your current fitness level into account and ramps up in small increments to prevent injury.

4. Going too fast.

Unless you’re an elite athlete, there’s no need to hit a fast pace or target time when running long; it’s more important to maintain a pace that’s easy and conversational in order to achieve optimal fitness for performance on race day.

AFTER the run…

5. Forgetting to refuel. 

Replenishing depleted muscles and replacing lost fluids are critical to recovery, so start with a carb-based post-run snack in the first 30 minutes after a run, drink 16 ounces of water for every pound lost (or until urine runs pale), and aim to have a balanced meal of carbohydrates, protein and healthy fats within two hours of completing your long run.

6. Skipping rest days.

Resist the urge to take a “more is more” approach with your workouts; taking a day off after a long run is almost as critical to your training as the long run itself, so know when back off in order to push hard later.