Hyperthyroidism (overactive thyroid) can cause rapid weight loss, an unusually fast heartbeat, and anxiety, while hypothyroidism (underactive thyroid) can trigger constipation, mental fogginess, weight gain, and extreme fatigue. (mindbodygreen.com)
A 12 - ounce cola has 35 mg of caffeine, but some of the newest energy drinks contain 14 times more — enough caffeine to lead to anxiety, insomnia, dehydration, stomach woes, or a dangerously fast heartbeat in some people (and it could pose special dangers to pregnant women). (health.com)
Fast heartbeat early Morning, sometimes Midway slight nausea, some days difficulty to function, getting overwhelmed and exhausted and have to lie down every 2 hours whereby 2 hours cardio training in the morning were not a problem. (tctmed.com)