I am nearly 63 years of age and all of my life I experience discomfort during the summer months - namely a pounding heart and with increasing temperature palpitations when I am outside walking about. I have recently had all the blood tests that relate to the functioning of the heart - thyroid, liver, kidneys, blood sugar level and cholesterol level are all OK - in fact magnificent. Heart stress test (heart ultrasound) showed that heart is structurally sound, strong pulse, no palpitations during testing, no arrhythmias and no blockages. Of course the test was on a treadmill inside an airconditioned building and room. Cardiologist said that I am dehydrated (I consume 1 and a half quarts of springwater daily) and must increase this during summer to 3 quarts of water. In Sydney Australia we are experiencing heat wave conditions (40 degree Celsius plus) for a few days running - the heart holter recorded many palpitations because I forced myself to walk many miles from the mid morning until the early evening to get the recordings but was told by doctor that I do not have palpitations during the night when I am sleeping. I do not like experiencing these palpitations during the hot weather - I do not have a car and have to rely on my legs to convey me from point A to point B. Any comments or suggestions please on how I can find out why I get palpitations during the hot weather. Many thanks.