Abstract- Caffeine increases systolic blood pressure to extent of. 17%and mean arterial blood pressure by about 11%. Heart rate. was also increased. The increase in systolic blood pressure was. attributed more to the increased stiffness of the aorta and larger. blood vessels rather than increased stroke volume.
http://www.ijsrp.org/research-paper-0214/ijsrp-p2637.pdf
Atrial flutter is a milder form of atrial arrhythmia than is atrial fibrillation; the atrial rate is slower but still ≈300 activations/min. Often, every second beat is conducted to the ventricles, yielding a heart rate of ≈150 beats/min. Atrial flutter can progress to atrial fibrillation, and its causes are similar.
http://ajcn.nutrition.org/content/81/3/539.full
However, consuming a large amount of caffeine daily or more than 250 mg of caffeine at a time can cause some unwanted effects. Too much caffeine can act to can speed up the heart rate, which can be dangerous for those with diabetes and heart problems. Those suffering from heart disease should limit their intake of caffeine to avoid experiencing any problems.
http://getfit.jillianmichaels.com/caffeine-affects-heart-rate-1220.html
Caffeine has a number of metabolic effects on the body and may increase the heart rate in some instances. Caffeine is a naturally occurring stimulant found in over 60 plants. It is found in tea leaves used to make different teas, coffee beans, cacao pods used to make chocolate and kola nuts used to make some sodas.
http://getfit.jillianmichaels.com/caffeine-affects-heart-rate-1220.html
Under resting conditions, caffeine has been shown to cause increases in blood pressure (25, 27, 38) and systemic vascular resistance (6, 38). Moreover, it can provoke elevations in plasma renin activity (5, 27,39, 41) and presumably in plasma ANG II concentrations.
http://jap.physiology.org/content/85/1/154
Systolic blood pressure and MAP were also higher during exercise plus caffeine; however, these increases were secondary to the effects of caffeine on resting blood pressure. No significant differences were observed in heart rate, skin temperature, or rectal temperature.
http://jap.physiology.org/content/85/1/154
This study examined the acute effects of caffeine on the cardiovascular system during dynamic leg exercise. Ten trained, caffeine-naive cyclists (7 women and 3 men) were studied at rest and during bicycle ergometry before and after the ingestion of 6 mg/kg caffeine or 6 mg/kg fructose (placebo) with 250 ml of water.
http://jap.physiology.org/content/85/1/154
Caffeine with its multiple effects is (1) an adenosine receptor. blocker. (2) increasing levels of angiotensin II (3) increasing the. levels of catecholamines. In the present study, an increase in the values of heart rate. and blood pressure were noticed with the intake of caffeine when. compared to placebo.
http://www.ijsrp.org/research-paper-0214/ijsrp-p2637.pdf
A cardiac arrhythmia is when the heart beats out of rhythm sometimes missing a beat or beating twice in the time period that usually would be one beat. Since caffeine is a stimulant and speeds up heart rate, doctors believed that this effect could be dangerous for those with heart arrhythmias. Doctors once warned those with cardiac arrhythmias to avoid consuming caffeine, but this advice may be somewhat outdated.
https://www.caffeineinformer.com/caffeine-ok-for-those-with-heart-arrhythmias
Coffee intake in this study was high, as is usual in Scandinavia. The participants in the lowest quintile consumed an average of 248 mg caffeine/d, which is equivalent to 2–3 cups of coffee, and the intake of 997 mg caffeine/d reported by the top quintile is equivalent to ≈10 cups.
http://ajcn.nutrition.org/content/81/3/539.full
caffeine intake and heart rate
More than 250 mg of caffeine at a time can act to speed up the heart rate, which can be dangerous for those with diabetes and heart problems. 