ref exercise - cardio type exercise is problematic for many with tick borne illnesses - often leading to worsening symptoms
all cardio exercise - especially the more rigorous types - like jogging/running, cycling/spin, cross trainer etc are known to lower immune function for a day or so afterwards - which in itself can be detrimental in lyme etc al
there is also the issue of ischemia reperfusion in chronic disease states that include fibrin build up etc ( lyme, bart, babs etc ) - so often a person can do short bursts of exercise ok - using the reserves present in the tissues - but when they try to do sustained aerobic exercise those reserves are used up and the cells go into deficit - and this can make us worse than we were before, cause PEM like reactions, or just more free radical damage and worsen mitochondrial dysfunction.
however - on the other hand if we do no exercise even though we are ill - we will tend to spiral downwards as all humans need exercise to be healthy - and the muscles need to be move and used to be metabolically active and also hormonally active - which is all v important in chronic disease and recovery
the trick to exercising with chronic illness is in what type and how to go about
Burrascano - the father of all LLMD's has a very good section on this in his 2008 ILADs guidelines
that's defo worth a read - many LLMD's advise the same even today https://lymediseaseassociation.org/wp-content/uploads/2009/08/burrguide200810.pdf
using these principles it is possible to move forward, gain strength and fitness - even with lyme
i am now training with weights for 30mins 3x per week and walking 7 days per week - including the occasional hill walk
i wrote the below some time ago - will copy and paste it here in case its of some help
Exercise - what worked for me
1. avoid all aerobic exercise beyond brisk walking - sends me straight into PEM ( even if i run for 100yards !) instead focus on strength exercises - they help build the immune system - whereas aerobic causes the immune system to dip for 1-2 days afterwards. Burrascano in his famous guidelines gave the same advice
2. understand the concept of an envelope or window within which you must train - enough to give your muscles a signal to grow but not enough to overstress them or your system. This is the same as for healthy people and athletes etc - its just with PEM the window is much narrower - so you have to be v careful to train only within your window.
3. stick to fairly low reps - again avoiding the aerobic - generally less than around 20 or 25 is fine - I would say start with whatever weight you can comfortably do 20 reps with - or just bodyweight eg squats or press-ups - as your tendons etc will not be strong if you have been ill for years and you do not want to damage anything - using lighter weights and not straining will help build up strength without damaging yourself.
4. Do not train consecutive days - allow body time to recover. Especially important with Lyme even without PEM. Aim to build up to training 3 times a week - 45mins to 1hrs - all over workouts - but may need to start at 1x per week if your recovery is slow to begin with.
5. focus on doing more reps than last week and doing the entire workout in shorter time (more intensity = better for muscle stimulation) - add more sets as you feel able till you get to 1hrs or your desired workout.
6. Pick a time of day when you feel at your best to do it -it will not feel nice to begin with – so you will need your best bit of the day to help tackle it
7. make sure diet and sleep are conducive to recovery and therefore making progress–
a. general food quality,
b. sufficient high quality protein - approx. 2g per kg of body weight.
BTW, i could not train as my fatigue was too severe and PEM also, until i changed to eating a Keto wholefoods diet - my energy took a useful step up within a week or so of doing that.