Heart Rate

Author: Gianpiero Pescarmona
Date: 13/08/2011


Heart rate is the number of heartbeats per unit of time, typically expressed as beats per minute (bpm). Heart rate can vary as the body's need to absorb oxygen and excrete carbon dioxide changes, such as during exercise or sleep.

Heart rate increases any time tissues are unable to cope with the required work.

Factors affecting heart rate


Altered heart rate and sinoatrial node function in mice lacking the cAMP regulator phosphoinositide 3-kinase-gamma. 2007

Because cAMP is a critical determinant of heart rate, we investigated whether heart rate is altered in mice lacking PI3Kgamma.

Hypotension and cardiac stimulation due to the parathyroid hormone-related protein, humoral hypercalcemia of malignancy factor.1989

However, PTH appeared to exert greater efficacy and potency than PTHrp in increasing heart rate in vivo.

Adrenomedullin concentrations are elevated in plasma of patients with primary hyperparathyroidism. 2003

Serum i-PTH levels correlated positively with systolic blood pressure (SBP) (r = 0.510; P <.02), diastolic blood pressure (DBP) (r = 0.586; P <.01) and heart rate (HR) (r = 0.486; P <.043) only in hypertensive PHP patients.


Tachycardia is a resting heart rate more than 100 beats per minute. This number can vary as smaller people and children have faster heart rates than average adults.

Physiological condition when tachycardia occurs are

  1. Exercise
  2. Pregnancy
  3. Emotional conditions such as anxiety.

Pathological conditions when tachycardia occurs are:

  1. Fever
  2. Anemia
  3. Hypoxia
  4. Hyperthyroidism
  5. Hypersecretion of catecholamines
  6. Cardiomyopathy
  7. Valvular heart diseases


Diabetes heart rate

Diabetes heart rate

In most experimental animals (mouse, rat) diabetes is associated with decreased heart rate.
In man both increase (depending on autonomic neuropathy) and decreased heart rate is described.

Cardiovascular responses and endurance during isometric exercise in patients with Type 2 diabetes compared to control subjects. 2005 Med Sci Monit. 2005 Oct;11(10):CR470-7.


While it is well documented that diabetes impairs the microcirculation, its effect on isometric exercise has not been determined.


Isometric strength and endurance of the handgrip muscles for a series of 2 fatiguing isometric contractions at a tension of 40% of the maximum strength were assessed in 10 subjects with Type 2 diabetes compared to 10 control subjects; 5 minutes were allowed between the contractions. Blood pressure (BP), heart rate (HR), blood flow (BF) of the whole arm and of the skin on the chest and foot were measured.


Strength and endurance for the first contraction was the same in control subjects compared to subjects with Type 2 diabetes (p>0.05), but endurance of the second contraction was significantly less in subjects with diabetes (p<0.01). HR increased significantly (p<0.01) by over three fold during exercise in control subjects compared to subjects with diabetes. Resting and peak blood pressures were greater in subjects with type 2 diabetes compared to control subjects (p<0.01). Forearm blood flow was significantly lower at rest, during exercise and post exercise in subjects with diabetes compared to control subjects (p<0.01).


The results are probably explained by the damage to the microcirculation seen in subjects with diabetes.

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