Heart rate monitor
A heart rate monitor measures the number of heartbeats per time interval, for example heartbeats per minute ( heart rate ). The heart rate monitor is available in different designs of which the chest strap and bracelet are the best known.
history
First, modern heart rate monitors were designed for use by athletes and coaches in order to optimize the quality and effectiveness of training. Soon after, scientists examined the devices and used them in their work. Today, the range of heart rate monitors offers easy-to-use products for everyone interested in wellness , fitness and health . But there are also high-tech products that meet the wishes and needs of ambitious recreational and competitive athletes and are used in a variety of ways in scientific studies of heart rate and heart rate variability.
Use
The aim of heart rate-controlled training is to positively influence the limits of the individually different load areas (e.g. aerobic endurance area ( fat burning ), anaerobic endurance area, development area, competition-specific endurance, maximum load), e.g. to shift performance at the anaerobic threshold to higher levels . The exact determination of the performance limits in the context of a performance diagnosis requires, in addition to the heart rate measurement, the determination of lactate levels and / or an analysis of the breathing gases during exercise (spiroergometry).
In recent years, heart rate monitors have become fashionable due to their increasingly cheaper price. Since the physical reactions to stress are very different in every person and a measurement of the heart rate only allows limited conclusions to be drawn about energy or fat consumption, these measurements are not a substitute for careful observation of your own body.
At the same time, the heart rate monitor should be used by those who are not athletically trained, especially at an advanced age, as there is a risk that they do not yet know or overestimate the limits of their body's reasonable endurance. Even experienced athletes can be subject to this misjudgment in both cold and high temperatures, as the body has to perform significantly better under these conditions.
Functions
In addition to displaying the heart rate, different models offer additional functions. Starting with the alarm when a target zone is exceeded, via the calorie calculation function to the altitude, temperature or step counter and load meter (wattmeter), all possible information for effective endurance training can be called up. Depending on the model, the heart rate data can already be analyzed during the training or later using either average values or the entire heart rate file (after transferring to a PC ) in order to optimally analyze and control the training.
Designs
There are four different designs.
Chest strap
The chest strap is a common form of heart rate monitor. The chest strap is worn below the chest and measures the heart rate via two integrated skin electrodes (in the picture "chest strap" the corrugated areas of the chest strap). Strictly speaking, the R-impulses (in the picture “heartbeat” the highest upward-pointing spikes) are recorded, which are emitted through the skin . In order to keep skin resistance low, a film of moisture is required between the skin and the electrodes. During sporting activities, this forms very quickly by itself through the accumulation of body sweat under the chest strap. Otherwise, the electrodes must be moistened (electrode gel, water) before the chest strap is put on. The power supply is usually done by a lithium - button cell . The current heart rate value is transmitted as a VLF radio signal with a short range. A microcomputer in the form of a wrist watch is usually used as the receiving and evaluation unit. Modern, higher quality bike computers are also able to receive and evaluate the signal sent by the chest strap. Endurance training devices ( treadmill , cross trainer , ergometer , rowing ergometer ) with an electronic display often have the option of displaying and evaluating the signals from common chest straps. The chest strap is mainly used in endurance sports in order to optimize training and avoid overload.
Uncoded analog transmitters and receivers from different manufacturers can be compatible with one another.
The first wireless heart rate monitor (also known as a heart rate monitor , heart rate monitor or chest strap ) was introduced in 1983. It was the portable PE 2000 heart rate monitor from Polar Electro , which consisted of a receiver and a transmitter. The transmitter could be attached to the chest using either disposable electrodes or an elastic electrode belt. The receiver was a watch-like monitor that was worn on the wrist .
Alternatives to the chest strap
In the fitness area, stationary heart rate monitors are often used on the sports equipment itself, which record the heart rate via two electrodes that have to be grasped with the hands for the measurement. Other devices measure the heart rate on the earlobe. However, neither measurement method is suitable for the performance-oriented area.
Measurement on the wrist by light
The heart rate can also be measured optically on the wrist. The heart rate monitor in the form of an activity tracker is worn on the wrist like a wristwatch. The device emits light, mostly in the green wavelength range, into the tissue on the wrist and measures the reflected light. Since blood strongly absorbs light in this wavelength range, the measured light intensity fluctuates as the blood vessels pulsate. The heart rate is determined from this signal.
The photoplethysmographic process was already described in the 1990s and has been extensively studied. In 2013, the Canadian company Physical Enterprises presented a product with this technology in the form of a heart rate monitor at the ISPO . In the meantime, comparable products from many suppliers are available on the market that still differ greatly in the reliability of the pulse measurement during movement.
Measurement in the ear canal
Heart rate monitors now exist that measure optically in the external auditory canal.
See also
Web links
Individual evidence
- ↑ Peter Janssen: Endurance training. Endurance training. Training control via heart rate and lactic acid determination . 2003, ISBN 3-934211-43-7 , pp. 66-79 chap. "Heart rate and ambient temperature"
- ^ D. Rafolt, E. Gallisch: Influence of Contact Forces on Wrist Photo plethysmography - Prestudy for a Wearable Patient Monitor . In: Biomedical Engineering . Volume 49, Issue 1-2, pp. 22-26, ISSN 1862-278X (online).
- ↑ It gets under your skin . In: FAZ.net , July 26, 2013
- ↑ J. Parak, I. Korhonen: Evaluation of wearable consumer heart rate monitors based on photopletysmography . Engineering in Medicine and Biology Society (EMBC), 2014 36th Annual International Conference of the IEEE, 26.-30. August 2014. pp. 3670-3673
- ↑ Fitness bracelet: a toy for self-surveyors . In: FAZ.net , April 16, 2015
- ↑ Heart rate monitor in the ear. In: heise online. Retrieved September 20, 2016 .
- ↑ Development and conception of an auditory canal sensor for mobile pulse oximetry. In: ub.tum.de. Retrieved September 20, 2016 .
