Hi welcome to HCm
I have gone thru your query regarding nausea, light headedness and weakness after exercise .Though , it is a matter of concern but not cause for worry .
Working out is supposed to improve your health .
I would like to know since how long you are into exercising ? If you are new with it and overdoing it , more than your capacity ,occasionally , you might experience such symtoms .
In fact , when you work out , we are influenced by animea ,
dehydration,
low blood sugar levels, low/ high BP overexertion, and, quite possibly,
heat exhaustion .
Try to remove causes and help increase immunity to lead healthy life .
Start with mild exercises and gradualy excel .
Relax after every step
Do Yoga ,Pranayam ,Deep breathing - Inhale as deep as possible - Hold - Exhale -Hold - help to re-expand lungs help detoxing the inner system and boosting the energy by providing sufficient oxygen .
Kapal bhati Pranayam ,Bhramari , Omkar Naad ,
Meditation all help increase your Physical and mental strength . Do Practice under trained guide.
Include Fiberous & calcium-rich foods like yogurt , cheese and greens -a balanced diet containing all essential nutrients - fiber ,vitamins ,minerals fresh fruit , veges and antioxidants - Olives,
Aloe vera ginger , garlic , help alley inflammation & pains .
Turmeric powder , an antioxidant effective antibiotic helps alley pains and infection ,
Stay hyderated . Drink plenty of fluids to prevent dehydration. You may find that taking small, frequent sips of a beverage is easier on your stomach than trying to drink a whole glass at once. Drink lemon juice in a glass of water with a pinch of salt and black pepper , thrice a day , is very energetic , good appitiser and alley adverse feeling very fast .
Avoid fried , fast foods , tea , cofee , alcohol ,
smoking ,
constipation ,dehyderation
If you face problem on a frequent basis ,rush to your Doctor .Ultimately a diagnosis by a medical professional is necessary so that the appropriate treatment can be commenced as soon as possible.
Hope this helps solves your query .Take care , All the best .
Don't hesitate to get back if have any further query