It turns out that loud noise is not just annoying, but it also has significant negative effects in the body.
An intriguing study published in the journal Environmental Health Perspectives in 2004, reports that a single session of exposure to very loud noise (100 decibels) for 12 hours caused a significant increase of DNA fragmentation in the adrenal gland cells. These endocrine glands sit on top of the kidneys and release hormones in response to stress, such as cortisol and adrenaline, the fight or flight hormone.
Loud noise is a form of stress as well, called acoustic stress and this is probably why the adrenals were affected so much. The levels of the stress hormones were elevated in the blood following exposure to loud noise. Experiments with consecutive sessions of loud noise exposure (simulating situations of chronic exposure to loud noises, such as living in a big city) show that the levels of stress hormones in the blood reach maximum levels within 9 days and remained in those levels for the duration of the experiment.
Cells possess sophisticated molecular tools to repair DNA breaks within 2 hours (if both strands are broken) or 15 minutes (if only one DNA strand is broken). Interestingly, in the single exposure to loud noise study, cells were unable to repair their DNA even after a day of not being exposed to noise. This suggests that noise is not just harming the DNA or increases the stress hormones, but also diminishes the ability of cells to heal and restore their physiological functions. Somehow, the cellular mechanisms that restore genetic problems remain temporarily inactive after exposure to loud noise.
The cardiovascular system seems to be very sensitive to acoustical stress as well. A study published in 2003 shows that this may be just the tip of the iceberg, since heart cells actually suffer extensive structural and molecular damage following 12 hours of exposure to 100 decibels.
As with the adrenal gland cells, heart cells were unable to restore the genetic damages, even a day after the loud noise exposure. The specific studyalso reports swollen membranes in vital sub-cellular structures and an increase in oxidative stress in the heart cells.
1. Frenzilli G, et al., 2004. Effects of loud noise exposure on DNA integrity in rat adrenal gland.Environ Health Perspect. 112(17):1671-2.
2. Lenzi P, et al., 2003. DNA damage associated with ultrastructural alterations in rat myocardium after loud noise exposure.Environ Health Perspect. 111(4):467-71.
3. Soldani P, et al., 1999. Long-term exposure to noise modifies rat adrenal cortex ultrastructure and corticosterone plasma levels. J SubmicroscCytolPathol. 31(3):441-8.
4. Gesi M, et al., 2001. Time-dependent changes in adrenal cortex ultrastructure and corticosterone levels after noise exposure in male rats. Eur J Morphol. 39(3):129-35.
5. Stansfeld S & Matheson M. 2003.Noise pollution: non-auditory effects on health. Br Med Bull 68 (1): 243-257.
Eleni Roumeliotou is a geneticist and clinical nutritionist specializing in fertility and perinatal nutrition and lifestyle. She is the founder of Primal Baby, a health sanctuary for all things fertility and pregnancy. Eleni passionately helps women, who are trying to conceive or are already expecting a baby, to optimize their diet and lifestyle in order to conceive naturally and have the healthiest baby possible. Her passion is to empower women to take control of their fertility and their baby´s health, safeguarding the well being of the next generation, one baby at a time. You can read all of Eleni´s MOTHER EARTH NEWS posts here.
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