Why Does Your Body Need Time to Adapt When You Change Your Training Routine?
You decide to get back into exercise, try a different gym programme or increase your running distance. The first session feels manageable, so you carry on with your new routine.
Then the next morning arrives.
Your legs feel heavy, your shoulders are stiff, and movements that normally feel effortless suddenly require more effort. Even getting out of a chair reminds you that you trained yesterday.
This can happen because your body needs time to adapt when the demands of exercise change.
Training places physical demands on your muscles, joints, tendons and other tissues. With appropriate recovery and repeated exposure, your body can gradually become better equipped to handle those demands.
However, adaptation is not instant, and feeling sore is not a requirement for making progress. How your body responds depends on the exercise, its intensity, your previous activity levels and your recovery.
What does it mean for your body to adapt to exercise?
Exercise adaptation is the process through which your body responds to repeated physical demands.
Depending on the type of training, this can involve changes in muscle strength, cardiovascular fitness, coordination, movement efficiency and the capacity of tissues to tolerate particular loads.
For example, someone who starts resistance training may gradually become stronger as their muscles and nervous system adapt to the exercises. A new runner may find that a previously challenging distance becomes more manageable after consistent, appropriately paced training.
These changes occur over time, not after one workout.
Your body is responding to the demands you place on it, but it also needs enough recovery to manage those demands.
Why changing your workout can feel harder than expected:
You do not have to train intensely to challenge your body. Sometimes, simply doing something unfamiliar is enough to create a noticeable response.
1. Your muscles are doing something different
Your muscles respond to the type, intensity and duration of the work they perform.
If you introduce exercises you have not done recently, particularly movements involving controlled lowering or lengthening of the muscles, you may experience delayed-onset muscle soreness, commonly called DOMS.
This soreness often develops during the hours after exercise, may be most noticeable over the following one to three days, and then gradually settles.
It is different from the immediate burning or fatigue you might experience during a workout.
DOMS can occur after a new or demanding session, but it is not a reliable measure of workout quality. You can improve your fitness and strength without becoming very sore.
2. Your joints and connective tissues experience different demands
A new routine may involve more jumping, running, lifting, twisting or repetitive movement than you are accustomed to.
Muscles, tendons, bones and other tissues respond to loading in different ways and over different timeframes.
This matters because your cardiovascular fitness or muscle strength may improve faster than your tolerance for a particular repetitive activity.
For example, you might feel fit enough to increase your running distance substantially, but your body may not yet be accustomed to that volume of impact.
Feeling capable of doing more does not always mean increasing everything at once is the best approach.
3. Your coordination is still developing
A new exercise is not only a physical challenge. It may also be a coordination challenge.
When you learn a new movement, your nervous system needs practice to help you perform it more efficiently.
A new gym exercise, swimming technique or unfamiliar sports drill may initially feel awkward, even if you have a good general level of fitness.
With practice, the movement may become more familiar and require less conscious effort.
Why you should not increase everything at once:
Imagine you usually go for a short walk a few times a week. You decide to start running, add two gym sessions and join a weekend sports team, all within the same fortnight.
Each activity may be reasonable on its own.
Together, they create a substantial change in your weekly workload.
It can become difficult to work out which activity is contributing to soreness or fatigue, and you may have fewer opportunities to recover between sessions.
A more manageable approach is to introduce changes progressively.
Depending on your goals, you might initially increase one aspect of training, such as duration, frequency, resistance or intensity, while keeping the others relatively stable.
There is no single progression rate that suits everyone. Your starting fitness, health, training history and the type of activity all influence what is appropriate.
The aim is to challenge your body enough to encourage adaptation without repeatedly exceeding what it can comfortably manage.
Why does the same workout feel easy one week and difficult the next?
Your response to exercise can vary even when your programme stays the same.
Sleep quality, work stress, recent activity, illness, nutrition and the demands of previous sessions can all influence how a workout feels.
For example, a training session that feels comfortable after a good night’s sleep may feel considerably harder after several late nights and a physically demanding week at work.
This does not automatically mean you are losing fitness.
It may simply reflect the combined demands on your body at that particular time.
Adjusting the intensity of a session when you are unusually fatigued can be more useful than insisting on completing every workout exactly as planned.
When should you seek professional advice about training-related pain?
Consider speaking with an appropriate healthcare professional if your symptoms repeatedly return, are affecting your ability to train or perform everyday activities, or are not improving as expected.
An assessment may help clarify whether your symptoms are consistent with exercise-related soreness or whether another issue needs attention.
Depending on the problem, support from a GP, physiotherapist, sports medicine practitioner or another suitably qualified professional may be appropriate.
A chiropractor may also assess certain musculoskeletal complaints and discuss management options where appropriate. Recommendations should be based on your history, symptoms and examination findings, with referral when further medical assessment is needed.
FAQ
How long does it take for your body to adapt to a new workout routine?
There is no single timeframe. You may become more coordinated with a new exercise over several sessions, while improvements in strength, endurance and tolerance to training generally develop over a longer period. The timeframe depends on the activity, your starting point and how consistently you train.
Is it normal to feel sore after changing your exercise routine?
Mild muscle soreness can occur after unfamiliar or demanding exercise, particularly when the muscles are exposed to new movements. However, severe, sharp or worsening pain should not automatically be considered normal.
Should I keep exercising if I am still sore?
It depends on the severity and nature of the soreness. Gentle movement or a less demanding session may be suitable for ordinary muscle soreness, but avoid pushing through sharp pain, significant swelling or symptoms that worsen with activity.
Why do I feel more tired after starting a new exercise programme?
Your body may be adjusting to a higher overall workload. If tiredness persists or performance continues to decline, review your training volume, recovery, sleep and nutrition. Persistent or unusual fatigue may warrant medical advice.
Can changing my workout routine cause joint pain?
A change in training volume, movement or intensity may contribute to joint or tendon symptoms in some people. However, joint pain has multiple possible causes. Persistent or worsening symptoms should be assessed rather than assumed to be a normal part of adaptation.
If you have changed your training routine and are experiencing persistent aches or pain, an individual assessment may help you understand what could be contributing. Wellbeing Chiropractic has Clinics across Melbourne, Sydney and Brisbane. Book an appointment to discuss your symptoms, movement and training demands and explore appropriate next steps.
