There are many reasons why your energy levels may be low. For example, this could be caused by:
• Lack of sleep.
• Poor diet.
• Iron or vitamin deficiencies.
• Medication.
• Lack of exercise.
• Depression.
• Burnout or stress.
• Underactive thyroid.
• Low motivation.
To keep yourself energized, incorporate a balance of short- and long-term strategies.
• Rehydrate yourself.
• Use light.
• Take a walk.
• Listen to music.
• Eat healthier food.
• Exercise regularly.
• Find meaning.
• Look at your schedule.
Clever Journeys 
You nailed it! Also, if you do have a weak heart or blood pressure trouble, you can take Hawthorne Berry capsules. My holistic doctor told me to take them after I had a close shave with congestive heart failure. Have been taking them since May and feel better than I have in three years. Worked too hard and wore my heart out, but now my energy increases day by day. The good news is that they are cheap; under $20.00 a bottle, and available on line or at a good health food store. Just one more thing to add to your list!
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