There will be times when it will be inadvisable to exercise. The American College of Sports Medicine (ACSM) and the American Cancer Society (ACS) have developedl guidelines to help you determine if you should stretch instead of participating in more vigorous activity.
Stop Exercising If You Have:

• Chest pain or pressure
• Develop an irregular pulse or palpitations
• A resting pulse higher than 100 beats per minute
• Decreased heart rate or blood pressure during increased activity
• Excessive rise in blood pressure
• Recurring leg pain or cramps
• Sudden shortness of breath, muscular weakness or tiredness
• Sudden onset of nausea
• Blurred vision, dizziness, faintness or lightheadedness
• Vomiting or diarrhea within previous 24 to 36 hours
• Disorientation or confusion
• Pallor (paleness) or cyanosis (bluish skin)
• Fever
• Excessive fatigue
• Chronic muscle soreness that interferes with activities of daily living
• Bruises or swelling - may be a sign that a bacterial or viral infection is not healing or a sign the lymph system is not working
  

Treatment, Lab Values or Blood Cell Counts (from your doctor):

• High-dose intravenous (IV) chemotherapy within previous 24 hours
• Platelet count below 50,000/mm3
• White blood cell count below 3,000/mm3Absolute granulocyte count below 2,500/mm3

Additional Precautions:

• Reduce exercise intensity in hot or humid environments or above 5000 ft
• Avoid exercise when you experience tenderness in a joint that worsens with activity
• Avoid strenuous aerobic activity during viral infections such as the flu or an
  upper respiratory tract infection
  
• Limit or eliminate upper body strengthening if you have a port
• Avoid public gyms if you are within one year of a transplant
• Avoid pools with chlorine if undergoing radiation