Monitoring your body provides valuable information on your adaptation to training, your risk of injury or illness, and your readiness for the next hard training session. There are several good ways to determine when you are overreaching so you can avoid overtraining and remain healthy. You can use this information to improve your recovery by modifying your training schedule to your individual limits. A variety of apps exist for runners and other endurance athletes to monitor the key factors that influence recovery from training, such as resting heart rate and amount of deep sleep. These apps take just a few minutes each day; they make it easy to track both your training and recovery factors and typically provide warning signs when several factors are heading in the wrong direction for several days.
There are many ways to monitor your recovery, but the simplest measures are useful and the easiest to adhere to. In combination, these measures provide insight into your adaptation to training. Typically, when results on these measures decrease, running performance and recovery deteriorate a few days later. In addition to the details of your training, try tracking the following factors and review the data periodically to find the patterns that predict overtraining, illness, and injury. It is important to be as consistent as possible when measuring these factors.
Weight. Check your weight at the same time of day each day or several times per week. While weight may naturally fluctuate slightly from day to day, decreases in weight over a few days may indicate dehydration. Decreases in weight over a few weeks can indicate that you are not eating enough calories, have an illness, or are overtraining.
Morning heart rate. Your heart rate when you first wake up in the morning provides an indication of your recovery. It is important to check your heart rate soon after you wake because it increases as soon as you start thinking about your plans for the day and by about 10 beats per minute when you get up. In addition, waking to an alarm can increase your heart rate and make the data less reliable. To find your resting heart rate, therefore, wear a heart monitor or take your pulse immediately upon waking for several days. Your true resting heart rate is the lowest rate you find. If your morning heart rate is more than 5 beats per minute higher than usual, this may be an indication of inadequate recovery or may be the first sign that you are not well. Early detection can be particularly useful in preventing illness.
Environmental conditions. Record the temperature and humidity on hot days. Because of increased core body temperature and dehydration, your body undergoes substantially more stress when you run at 80 degrees Fahrenheit (27 degrees Celsius) and 80 percent humidity than at 60 degrees Fahrenheit (16 degrees Celsius) and low humidity. If you train hard or compete on a hot, humid day, the heat you generate can overwhelm your body's ability to eliminate heat, causing your core temperature to climb, which can increase recovery time. Similarly, as discussed in chapter 2, severe dehydration also increases recovery time. There's great variation in how runners are affected by heat. Monitoring these factors will reveal patterns that can help you make needed adjustments during a stretch of hot weather.
Hours of sleep. The number of hours you sleep is not particularly important for any one night. Over several nights, however, your quantity of sleep can influence your recovery and ability to adapt positively to training and can, in combination with other measures, explain a lack of recovery and indicate lifestyle changes required to enhance your running performance and help prevent illness or injury.
Quality of sleep. The quality of your sleep is arguably more important than the number of hours. Evaluate the quality of your sleep each night—How soundly did you sleep? Were you awake a lot in the middle of the night? Did you get out of bed feeling refreshed?—and try to be consistent in your assessment. A reduction in quality of sleep is often associated with overtraining. Reduced sleep quality can also be caused by nonrunning stressors, but the result for your running performance is the same. See “Sleep Better, Run Faster” on page 75 for how to maximize the recovery benefits of sleep.
Diet quality. Evaluate the overall quality of your diet each day. Did your meals cover your carbohydrate and protein needs? Did you get so hungry that you binged? Did the bulk of your calories come from healthy foods? Often, a lack of energy can be traced back to poor diet in the previous few days.
Hydration level. Dehydration has a negative effect on running performance and slows recovery from training. Evaluate your hydration level each day. Was your urine clear? Did you drink small amounts regularly so you seldom felt thirsty? Did your mouth and throat often feel dry? Your daily weight also provides a good indication of your hydration level.
Muscle soreness. It is not unusual for runners to have slightly sore muscles most of the time. An increase in muscle soreness can be due to a hard workout or running downhill. Evaluate your general muscle soreness each day. Did your soreness lessen after a few miles of running? Did your soreness seem explainable by your most recent workouts? If increased general muscle soreness lasts more than 4 or 5 days, it is likely that you are ill or overreaching. Soreness in a specific muscle indicates a potential injury, whereas more general muscle soreness provides an indication of your recovery and adaptation to training.
Energy level. An assessment of energy level is one of the best indications of recovery from training. Evaluate your energy level each day. Did you have the energy to accomplish your running and daily life goals? Did you feel alert and focused when running or performing a task? If your energy level is reduced for more than 3 days, it is important to determine the cause of the reduction. Typical causes of reduced energy levels are lack of carbohydrate intake, training hard too many days in a row, illness, low iron levels, dehydration, and lack of sleep. By reviewing your training and considering your lifestyle factors, you should be able to identify the likely cause of a low energy level.
Heart rate at a standard pace. If your heart rate at a set pace is more than about 7 beats per minute higher than usual, you may not be recovered from your previous training sessions. For example, if your heart rate at an 8-minute-per-mile pace is typically 145 beats per minute, and one day you find it is 155 beats per minute at that pace, you likely need additional recovery before doing your next hard training session. Heart rate during running at a given pace varies by a few beats per minute from day to day, and it is also influenced by factors such as dehydration and hot or humid conditions, so take this into consideration in evaluating the implications of a higher-than-usual heart rate.