Discover How Our Bodies Adapt to Exercise

We live in a world that seems to move much too fast: news served in 30-second sound bites, take-out meals, promises of a new supplement which will make you fit in 30 days. But the results of exercise take time. Any gain fast-won is fleeting. Health measures, be it developing strength to move furniture with ease, making bones robust enough to tolerate the occasional fall, or improving one’s mood, looks, and energy levels are won through repetitive, lasting exercise habits. There are no short-cuts.

Understanding some of what exercise does to our bodies may encourage you to be patient in looking for health improvements and stay with an exercise habit to maintain these benefits.

How bodies adapt to exercise

Our bodies adapt well to exercise, making positive changes in an astonishing variety of markers of good health. The body reacts to exercise with changes in body structure and chemistry as well as changes in nervous system efficiency, and brain function. These changes are called adaptations, and they occur over time with certain systems realizing faster alterations than others. Adaptations occur at all levels from tiny sub-cellular organelles to whole body systems such your skeleton.

Sub-cellular adaptation

Remember those mitochondria from high school bio? These organelles exist within single cells and require 3-4 weeks of training to appreciably increase in size and number, while chemical changes allowing increased energy production within the cell occur with days of starting exercise. These adaptations lead to improvements in our overall metabolic health.                                  

Neuromuscular adaptation

Positive changes in muscle growth start with the nervous system improvements which can be measured in a laboratory within 2 weeks of starting an exercise program. You might notice an initial period (first 1-3 weeks) of quick increases in the amount of weight you can lift. This is the result of neural changes allowing the body to recruit the muscle tissue already in existence more efficiently. Improvements in actual muscle tissue growth, measured by biopsy in laboratories, will take generally 6 weeks to become detectable. Visible muscle hypertrophy (growth) occurs over 8-12 weeks.

Skeletal adaptation

Bones respond to weight-bearing and resistance exercise with bone cells (osteocytes) detecting mechanical strain which triggers bone remodeling. Bone mineral density will increase, and changes occur to bony architecture resulting in a more robust, fracture-resistant skeleton. These adaptations take 6-12 months.

Consistency is key

In summary, adaptation times vary within our biological systems. They also vary from person to person. The key point is that consistent exercise leads to positive changes throughout our bodies and brains. These changes take time, and require consistent upkeep once acquired. We understand that the thought of maintaining consistent exercise for the rest of one’s life may be daunting. Below are some strategies that you can use to create a positive relationship to exercise:

• Be patient: see above.

• Set realistic expectations: expecting too much, too soon sets one up for disappointment.

• Make exercise a habit: research continues to emerge suggesting evidence-based methods for making a desired action, exercise in this case, more automatic.

• Celebrate small accomplishments: given that our most-desired results take time, notice small achievements such as reaching your weekly cardio goal, or recognizing that you’ve increased the weight you can move for a specific exercise.

• Exercise with a friend (accountability), or a dog; set dates.

• Explore a variety of exercise modes, particularly in working toward your cardio goal.

• Keep a journal.

• Reward yourself: allow yourself to listen to your favorite podcast only while using the treadmill, for example.

• Plan an active vacation or athletic event and train for it.