What teaching is most important for a client beginning a new exercise program?

Exercise initiation guidance for previously sedentary clients: (1) Medical clearance — recommended for adults 45+ starting vigorous exercise, those with chronic conditions, or those with cardiovascular risk factors; ECG stress test for some; (2) Start gradually — '10% rule' for runners (don't increase weekly mileage by more than 10%); applies generally to intensity, frequency, duration; (3) Warm up — 5-10 minutes of low-intensity activity to raise heart rate, increase blood flow to muscles; (4) Cool down — 5-10 minutes of decreasing intensity; stretching during cool-down; (5) FITT principle for prescription: Frequency (how often), Intensity (how hard), Time (how long), Type (what kind); (6) Variety — combine aerobic (walking, swimming, cycling), strength (resistance training 2+ days/week), flexibility (stretching, yoga), balance (especially for older adults); (7) Hydration — water before, during, and after exercise; (8) Nutrition — adequate fuel and recovery foods; (9) Equipment — proper shoes, supportive clothing, helmets and safety gear; (10) Listen to the body — distinguish discomfort (normal) from sharp pain (stop); rest days important; (11) Signs to stop exercise: chest pain, severe shortness of breath, dizziness, irregular heartbeat, severe joint pain. Realistic goal-setting: 150 minutes moderate or 75 minutes vigorous aerobic exercise per week, plus strength training 2x/week — but starting with any activity is beneficial. Enjoyable activities promote adherence. Tracking progress motivates continuation.