Research | April 2014 Hearing Review
If we are to be proponents of the idea that better hearing leads to better health, then we should also recognize that a more fit body can positively impact hearing.
Editor’s Note: This is Part 2 of an article that originally appeared as Chapter 6 in the book, The Consumer Handbook on Hearing Loss & Hearing Aids: A Bridge to Healing, 4th edition, edited by Richard Carmen, AuD (Auricle Ink Publishers, 2014).1 It is reprinted here in an abridged version with permission from the publisher. Part 1 of this article can be accessed by clicking here.
Noise exposure and age seem to be two main culprits associated with hearing loss. Given enough time and exposure to noise at either work or leisure, or short-term exposure to very loud noise (such as from firearms or loud music), hearing acuity is likely to decline with age. However, recent evidence has accumulated identifying factors that have little to do with age or noise exposure—yet have a significant influence on hearing acuity. Some of these factors include marital status, education, personality type, and health and fitness.
Body Composition and Hearing
In addition to biomarkers for cardiovascular health and fitness, VO2max, and blood pressure (another component of fitness), body composition has been shown to be associated with hearing acuity.2 Body composition can be assessed in many different ways, including weight alone, height to weight ratio, percent fat, percent lean body mass, waist circumference, and waist-to-hip circumference ratios.
The goal of these measurements is to determine if a person is a healthy weight for their height, underweight, overweight, or obese. Being underweight is a risk factor for frailty and degenerative diseases, such as osteoporosis and cancer. The majority of Americans are overweight or at risk for being obese due to lifestyles of physical inactivity and overconsumption of food. Conditions of being overweight or obese are directly associated with many age-related diseases including heart disease, diabetes, arthritis, and certain types of cancer. Typically, people who are overweight are also less physically active than those with healthy body weight, which may explain the usual lower cardiovascular (CV) health and fitness of overweight individuals.
Being overweight typically refers to excessive body weight relative to height. While some people use subjective ways (eg, How do my clothes fit? How do I feel?) to estimate whether they are too fat or too thin, the more popular and accurate way to assess body composition is by using height and weight data to calculate body mass index (BMI). For readers interested in this formula, BMI is represented by weight in pounds divided by height in inches squared (weight x height) and multiplied by 703. (For example, if you weigh 140 pounds and are 5 feet 5 inches tall, your BMI would be calculated as: 140 ÷ (65 x 65) x 703 = 140 ÷ 4225 x 703 = 23.3.) Another option is to use a chart that incorporates this formula into a wide selection of heights and weights (Figure 1) to provide BMI values.
Healthy BMI values range from approximately 19-25 and depend on the proportion of weight for one’s height to get a sense for being under- or overweight depending on height. However, BMI values are not the same as percent body fat. Obesity specifically refers to excessive body fat, often measured by bioelectrical impedance, skin fold calipers, or air displacement (among others). Women with total body fat over 30% and men with total body fat over 25% are considered to be obese.
It should come as no surprise that, compared to adults who have healthy body compositions, adults who are either overweight or obese suffer from more diseases, including hypertension, hyperlipidemia, and diabetes. In the past decade, evidence has emerged that waist circumference is a powerful predictor of obesity risk and that when coupled with BMI, both waist circumference and BMI predict health risk, including premature death, better than BMI alone.3 This intriguing finding (that a measurement as simple and low cost as waist and/or hip circumference can be such a powerful indicator for health and disease) is finding its way into physicians’ offices across the country as part of routine health screening.
BMI and hearing sensitivity. Preliminary data from our laboratory indicate that body composition is an important health-related component associated with hearing sensitivity. Specifically, BMI is inversely related to hearing sensitivity. That is, the higher the BMI, the poorer the hearing acuity. In a study of 67 middle-age adults, individuals who were classified with normal BMI levels had normal hearing, while those with BMI values classified as obese had poorer hearing at 8000 Hz.4 Figure 1 is a chart for determining BMI based on height and weight with designated risk zones, and different versions of this chart are widely available online.
BMI is not a direct measure of body fat, nor does it provide a map for where fat is distributed around the body. Nevertheless, body mass index has been shown in some studies to correlate directly with risk for the cardiovascular rate of disease (morbidity) and mortality.5 That is, the higher the number, the greater the risk of cardiovascular disease. In a recent study of college-age students, a trend was observed whereby the higher the body mass index, the worse the hearing acuity.
Waist-to-hip measurements provide more information regarding fat topography and provide a better geographic map on where body fat is distributed. “Apples” (the people who store more fat centrally or in the abdominal area) have been reported to be at higher risk for developing heart disease and type 2 diabetes.6,7 Of particular interest in our preliminary studies, waist-to-hip ratio is observed to be inversely related to hearing in a similar way as body mass index (Figure 2). That is, individuals having more of an “apple” body shape had poorer hearing when compared with “pear” body shapes or healthier BMI and waist-to-hip values. This simple no-cost method of assessing health using waist and/or hip circumference measurements may be a valuable biomarker for obesity, cardiovascular disease, metabolic disease, as well as hearing loss.
Factors Contributing to Hearing Loss Other Than Noise
- Genetic conditions. A number of health and inheritance factors contribute to the progression and severity of individual hearing loss within or outside our control. They range from genetics and medical conditions, such as diabetes, cancer, and HIV, to personality and behavioral factors.8 In some cases, hearing loss occurs with age; in other cases, it is observed at birth.
- Diabetes. The prevalence of diabetes mellitus in the United States in both children and adults is 25.8 million people, with 1.9 million new cases reported in 2010 alone. Most disconcerting is that, according to the American Diabetes Association, an additional 79 million people are prediabetic. Diabetes also contributes to hearing damage by causing metabolic and vascular changes in the body including in the ear. Diabetes is a known cause of microvascular disease, and believed to contribute to hearing loss by causing less blood flow and poorer quality blood to reach the peripheral parts of the body, including the ear and probably the eyes.
- A recent study on vision found that older women with damage to the retina (retinopathy) were twice as likely to have hearing loss in lower frequencies.9 This study also showed that, in patients with hearing loss and diabetes, worsening creatinine levels led to poorer hearing. That is, as blood, muscles, and urine became less efficient at dumping waste products, the likelihood for hearing loss increased. Therefore, cardiovascular fitness may have protective effects on the rate of diseases such as diabetes.
- HIV. A final medical condition associated with increased risk of hearing loss is the human immunodeficiency virus infection (HIV). Individuals with HIV are shown to have a higher risk of developing sudden sensorineural hearing loss than those without HIV, particularly males between the ages of 18 and 35. And this population is more than 2 times more likely to develop sensorineural hearing loss than those in the general population without HIV.10
- Stress. Personality is another nonacoustic factor that may contribute to hearing loss. In general, it has been found that individuals who are more prone to stress may be more likely to develop temporary hearing loss than those who are less stress-prone when presented with the same amount of noise exposure.
This was confirmed in a research study in which individuals were sorted into two groups: the Type A (coronary-prone) group consisted of individuals who tended to have higher reactions to stress, and the Type B (non-coronary-prone) group. Studies have found that Type A personalities tend to have longer periods of peripheral blood vessel constriction leading to reduced blood circulation in the inner ear. In other words, when you tense your body, you tend to reduce blood flow. This might mean sensing a bit of numbness in your extremities, colder fingers, muscle ache or cramps, or a sense of fatigue. This reduced circulation placed the individuals at a higher risk for developing temporary hearing loss than their Type B personality counterparts.
A similar study confirmed the relationship between hearing loss and stress. They found that Type A (coronary-prone) personalities had poorer hearing levels at specific tones following 10 minutes of noise, and following 10 minutes of noise accompanied by exercise than did their Type B counterparts.8 The changes in temporary hearing sensitivity in the Type A personality group occurred independent of differences in circulatory and heart rate measures (compared with the control group) following either noise, or noise and exercise.
These studies indicate that stress factors other than increased heart rate and blood pressure contribute to temporary threshold shift (TTS). Permanent threshold shift represents the most common hearing effect of medical factors and loud noise, and is related to a number of factors including the number of exposures and exposure duration. From this discussion, it is apparent that several different medical and personality factors may contribute to hearing loss.
What You Can Do
As you continue to age, knowledge of many factors that influence hearing sensitivity, especially those that can be modified, may empower you to adjust certain aspects of your lifestyle to generate a positive influence on life quality and life expectancy.
In addition to adding aerobic exercise to your life as explained in this 2-part article, you can purchase a pedometer to track your number of footsteps (or mileage) to be sure you are attaining the desirable targets. If you want to exercise or walk to the sound of music, keep the volume at a level where you can hear someone within arm’s reach speaking to you.
Pay close attention to your body weight and fat storage by monitoring your BMI and waist and hip circumference. Obesity and “apple” shapes where excess fat is stored in the abdominal region add to risk for CV disease and hearing loss.
Find ways to reduce stress in your life and increase your ability to stay calm regardless of your personality type.
In the words of Kofi Annan, information can be liberating, since it can spring you into action with the assistance of healthcare professionals, to undergo appropriate interventions designed to maintain or improve your life, and subsequently provide you with more healthy, productive, and even happier years.
1. Alessio HM, Hutchinson Marron K. Fitness and better hearing. In: Carmen RE, ed. The Consumer Handbook on Hearing Loss & Hearing Aids: A Bridge to Healing. 4th ed. Sedona, Ariz: Auricle Ink Publishers; 2014. Available at: http://www.hearingproblems.com
2. Kolkhorst FW, Smaldino JJ, Wolf SC, et al. Influence of fitness on susceptibility to noise-induced temporary threshold shift. Med Sci Sports Exerc. 1998;30:289-93.
3. Janssen I, Katzmarzyk PT, Ross R. Waist circumference and not body mass index explains obesity-related health risk. Am J Clin Nutr. 2004;79:379–84. Available at: http://ajcn.nutrition.org/content/79/3/379.full.pdf
4. Wagner S, Lenzini S, Wharton T, et al. Personal listening device use, hearing, health and fitness. Poster session presented at: Annual convention of the Ohio Speech Language and Hearing Association; Columbus, Ohio; March 2013.
5. Frankel S, Elwood P, Smith GD, et al. Birthweight, body mass index in middle age, and incident coronary heart disease. Lancet. 1996;348:1478-1580.
6. Jacobs EJ, Newton CC, Wang Y, et al. Waist circumference and all-cause mortality in a large US cohort. Arch Intern Med. 2010;170:1293-1301.
7. Despres JP, Lemieux I, Prud’homme D. Treatment of obesity: need to focus on high risk abdominally obese patients. BMJ. 2001;322:716-720.
8. Hutchinson K, Alessio HM. Influence of personality type on susceptibility to the effects of noise exposure. Journal of Psychological Type. 1996;39:30-36.
9. Kakarlapudi V, Sawyer R, Staecker H. The effect of diabetes on sensorineural hearing loss. Otol Neurotol. 2003;24:382–386.
10. Lin C, Lin S, Weng S, et al. Increased risk of sudden sensorineural hearing loss in patients with human immunodeficiency virus aged 18 to 35 years: a population-based cohort study. JAMA Otolaryngol Head Neck Surg. 2013;139:251-255.
About the authors: Helaine M. Alessio, PhD, is a professor and chair of the Department of Kinesiology and Health at Miami University in Oxford, Ohio. Kathleen Hutchinson Marron, PhD, is chair of the Department of Speech Pathology and Audiology and is on the executive board of the Center for Disability Studies, and is a professor at the Center for Human Development, Teaching, and Learning at Miami University.
Original citation for this article: Alessio H, Hutchinson Marron K. Fitness and Better Hearing, Part 2. Hearing Review. 2014;21(4):34-37.