# Exercise as it relates to Disease/Aerobic exercise and obstructive sleep apnea
## What is Obstructive Sleep Apnea

Apnea is defined as a ‘cessation of breath’ for at least 10 seconds. Obstructive Sleep Apnea(OSA) also called Obstructive Sleep Apnea Syndrome(OSAS) is the most common form of sleep apnea, affecting 9% of middle aged men and 4% of women. It occurs when there are repeated episodes of complete or partial blockage of the upper airway during sleep. During a sleep apnea episode the diaphragm and chest muscles work harder to open the obstructed airway (that is blocked by the collapse or narrowing of the soft tissue) so air can flow to the lungs. Breathing resumes with a loud gasp, snort or body jerk. These episodes interfere with sleep patterns, can reduce the flow of oxygen to vital organs, and cause irregular heart rhythms.

## Signs & Symptoms

* Daytime sleepiness or fatigue
* Dry mouth or sore throat upon awakening
* Headaches in the morning
* Trouble concentrating, forgetfulness, depression, or irritability
* Night sweats
* Restlessness during sleep
* Sexual dysfunction
* Snoring
* Sudden awakenings with a sensation of gasping or choking
* Difficulty getting up in the mornings

## Risk Factors
### Obesity

Obesity and indicators for central obesity, such as neck circumference, is one of the main risk factors for developing OSA. Ways in which obesity predisposes to OSA include:
* Narrowing of upper airway
* Alterations in upper airway function
* Reductions in lung volume
Studies have shown the a 10% in weight was associated to a 6-fold increase in risk for developing OSA

### Other Risk Factors

* Gender - men have twice the risk of developing OSA. This could be due to upper airway fat deposition, larger amounts of soft tissue in the upper airways and hormones are believed to play a role.
* Ethnicity - African Americans and Asians appear to be at a greater risk
* Family history/genetics - The risk of OSA in an individual rises with the increasing number of affected relatives
* Nasal obstruction - Increases risk of OSA through the increased negative upper airway pressure produced by inspiratory efforts against a partially occluded nasal airway, turbulence, nasal reflexes, and snoring causing damage/edema to the upper airway soft tissues.
* Alcohol - Relaxes the upper airway and may induce OSA on healthy people or chronic snores. And increases the duration and frequency of episodes in those who suffer OSA.
* Smoking - Increase risk could be due to smoking-related airway inflammation and interference in sleep.
Underlying diseases such as hyperthyriodism and acromegaly and structural abnormalities have also been identified as risk factors.

## Long Term Effects

* Cardiovascular disease
* Heart failure
* Cardiac arrhythmias
* Premature death
* Development of diabetes

## Treatment

Common treatments used for OSA are Continuous Positive Airway Pressure(CPAP) and Mandibular advancement devices which pumps steams of air through a mask to hold open the airways. Avoiding alcohol and smoking is recommended and weight loss for those who are overweight.

## Effects of aerobic Exercise

Exercise has been shown to be an effective intervention and prevention strategy for OSA as it reduces both the cardiovascular risk factors like blood pressure and other comorbidities. Although it has not yet been found that exercise on its own would benefit OSA sufferers, research has shown that exercise should be used as an adjunct to primary treatment with CPAP. As regular aerobic exercise is associated with body weight maintenance, and at higher volumes weight loss, recommendations for increased frequent physical activity accompanying primary treatment from CPAP may be a way to increase energy expenditure and reduce secondary risk factors in OSA. Aerobic exercise training may reduce OSA severity, improve exercise capacity and also improve daytime sleepiness, and improve quality of life and mood state.

## Recommendations
### Aerobic exercise

| Frequency | 3-4 sessions/week |
| Intensity | Moderate- 60% of heart rate reserve (HRR) |
| Type | Walking, Cycling, Swimming |
| Time | 150min/week |

## Recommended Reading

Sleep apnea fact sheet
Autralasian Sleep Association

## References

* 1 2 3 4 5 Lawati A, Patel S, Ayas N. (2009) 'Epidemiology, risk factors, and consequences of obstructive sleep apnea and short sleep duration.'51(4):285-93. doi: 10.1016/j.pcad.2008.08.001.
* 1 2 Understanding Obstructive Sleep Apnea, 2005-2014. WebMD
* 1 2 Peppard T, Young M, (2000)'Longitudinal study of moderate weight change and sleep-disordered breathing'pp. 3015–3021
* ↑ Redline S, Tishler P & Tosteson P. 'The familial aggregation of obstructive sleep apnea' Am J Respir Crit Care Med, 151 (3 Pt 1) (1995), pp. 682–687
* ↑ Mirza N & Lanza D. 'The nasal airway and obstructed breathing during sleep'. 32 (1999), pp. 243–262
* ↑ Scalan M, Roebuck T & Little P. 'Effect of moderate alcohol upon obstructive sleep apnea'.6 (2000), pp. 909–913
* ↑ Kashyap R, Hock L, Bowman T.'Higher prevalence of smoking in patients diagnosed as having obstructive sleep apnea'Sleep Breath, 4 (2001), pp. 167–172
* 1 2 Javaheri S, Parker TJ, Liming JD, Corbett WS, Nishiyama H, Wexler L & Roselle GA, (1998) 'Sleep apnea in 81 ambulatory male patients with stable heart failure. Types and their prevalences, consequences, and presentations'. PubMed 2;97(21):2154-9.
* ↑ Gunnarsson SI, Peppard PE, Korcarz CE, Barnet JH, Aeschlimann SE, Hagen EW, Young T, Hla KM & Stein JH, (2014) 'Obstructive sleep apnea is associated with future subclinical carotid artery disease: thirteen-year follow-up from the wisconsin sleep cohort'. PubMed (10):2338-42. doi: 10.1161/ATVBAHA.114.303965.
* ↑ Peppard PE, Young T, Palta M & Skatrud J, (2000) 'Prospective study of the association between sleep-disordered breathing and hypertension.'PubMed 342(19):1378-84. doi: 10.1056/NEJM200005113421901
* ↑ Gami AS1, Pressman G, Caples SM, Kanagala R, Gard JJ, Davison DE, Malouf JF, Ammash NM, Friedman PA & Somers VK, (2004) 'Association of atrial fibrillation and obstructive sleep apnea.'Pubmed 110: 364-367 doi: 10.1161/01.CIR.0000136587.68725.8E.
* ↑ Qaseem A, Holty J, Owens D, Dallas P, Starkey M, Shekelle P.(2013).'Management of Obstructive Sleep Apnea in Adults: A Clinical Practice Guideline From the American College of Physicians.'. Annals of Internal Medicine. doi:10.7326/0003-4819-159-7-201310010-00704. PMID 24061345
* 1 2 3 Silva R, Belli K, Carissmimi A, Fiori C, Faria C & Martinez D. 'Are there benefits of exercise in sleep apnea?' Sleep sci2011;4(2):61-67
* ↑ Wijnen H, Boothroyd C, Young MW, Claridge-Chang A. Molecular genetics of timing in intrinsic circadian rhythm sleep disorders. Ann Med. 2002;34:386–393
* ↑ Kline C, Crowley E, Ewing G, Burch J, Blair S, Durstine J, Davis J & Youngstedt S (2013)'Blunted heart rate recovery is improved following exercise training in overweight adults with obstructive sleep apnea.'PubMed 167(4):1610-5. doi: 10.1016/j.ijcard.2012.04.108.
* ↑ Ueno L, Drager F, Rodrigues A, Rondon M, Braga A, Mathias W, Krieger E, Barretto A, Middlekauff H, Lorenzi-Filho G & Negrão C. (2009) 'Effects of Exercise Training in Patients with Chronic Heart Failure and Sleep Apnea.' 32(5): 637–647.
* ↑ Kline C, Crowley E, Ewing G, Burch J, Blair S, Durstine J, Davis J & Youngstedt S. 'The effect of exercise training on obstructive sleep apnea and sleep quality:a randomized controlled trial.' SLEEP 2011;34(12):1631-1640.