How to Use Fitness Trackers for Sleep Improvement

By Brandon Peters, MD

If you have purchased a fitness tracker, like millions of others, you may wonder how to use the wearable device to improve your sleep. These sleep trackers may provide some valuable insight into an important of health and well-being. They can also be completely useless. What do these wearables measure? How accurate are these measurements? How do they differ from medical sleep studies? Importantly, how should the information collected be used to make changes to improve sleep and reduce insomnia? Let’s consider these important questions and discover how to use fitness trackers to sleep better.

What Sleep Metrics Do Wearable Fitness Trackers Measure?

There are many wearable devices available that can be used to track fitness goals and even sleep. Some of the most popular options include the FitBit and Apple Watch. There are also smartphone apps, smart beds, mattress pads, and stand-alone products that can track sleep metrics. What kind of information is collected?

Movement

Most devices are tracking movement. There are variations on actigraphy. This measures movement velocity and direction with an accelerometer. It may be assumed that stillness equates with sleep, and movement corresponds with activity.

Biometrics

Sophisticated devices may detect breathing patterns, heart rate, or oxygen levels. It may even be possible to measure electrical current conductivity within the skin. Sound may also be detected, sometimes via vibration, that may correspond with snoring.

Schedule

Timing is important to sleep quality. It may also be possible to input information about your bedtime, wake time, and even naps to help track sleep patterns over an extended period. This information is often collected via sleep logs and may help to identify circadian rhythm disorders.

Environmental Characteristics

Some devices may also be able to identify other environmental characteristics, such as lighting, temperature, and noise. These may be useful to support the other variables that are measured. If the room is dark, it is nighttime, and a person is not moving, it is more likely that they would be asleep.

How Accurate Are Sleep Trackers?

It is natural to wonder how accurate sleep trackers are in measuring the characteristics of sleep. If you were dieting and using a scale, you would certainly want to ensure the weight that it was reporting was close to reality, both true to the actual value (accuracy) and repeatable over time (precision).

Sleep is more than just lying still. Someone could lie perfectly still and a wearable may believe this inactivity corresponds to sleep. Similarly, movements may occur during sleep that do not necessarily correspond with complete wakefulness. Many awakenings will go unnoticed by an individual as it can take more than 5 minutes of wakefulness before a memory is generated.

It is possible that other measurements may help to strengthen the accuracy of these observations. Breathing becomes very regular in deep, slow-wave sleep. This may indicate a person has fallen asleep. Heart rate patterns, oxygen levels, and other biometric measurements may help improve accuracy.

Unfortunately, many sleep trackers are products that are designed for consumers without scientific validation. The measurements may not be either accurate or reproducible. Artifact may interfere with the measurements. Moreover, the collected information may not correspond to the gold standard measurements.

Comparing Information to Sleep Testing and Studies

When sleep is measured by a diagnostic polysomnogram in a sleep center, there are a number of important characteristics. These include the brain wave activity as measured by EEG, muscle tone, the movement of eyes, other body movements, and sometimes additional data. No fitness trackers are able to collect all of these data. The nightly sleep patterns they provide—showing light, deep, and even REM sleep—are not as accurate as the information gathered with formal sleep testing.

In fact, sleep trackers are perhaps closest to an actigraph, a small wristwatch-like device that measures movement to give a rough pattern of sleep and wakefulness. These data can be very difficult to interpret, even by expert researchers, and the messy signals may be inscrutable to an algorithm. What is a person to do? How can you use the data that is collected via a wearable sleep tracker to optimize your sleep?

How to Use Data to Improve Sleep

Though the data collected by wearables or other sleep trackers may be imperfect, it can still be useful. It may be important to take a bird’s eye view of the information that is collected. Consider these simple recommendations:

1. Trust your own experiences.

Before buying into the data collected by an imprecise, and possibly wholly inaccurate device, reflect on your own sense of how you are sleeping. Do you recall waking 30 times in the night? Do you remember dreaming, even though the device reported no dream sleep? Are you having difficulty explaining the sleep pattern it provides? If you feel like you are sleeping well, consider simply ignoring the sleep data your device may provide.

2. Use the information to reinforce good sleep habits.

It is helpful to keep a regular sleep-wake schedule. Get up at the same time every day, including weekends. Try to get 15 to 30 minutes of sunlight upon awakening. Go to bed at about the same time every day. Go to bed when you are feeling sleepy. Try to get at least 7 to 9 hours of sleep nightly, meeting your own sleep needs. Avoid naps when possible. If the sleep tracker helps to reinforce a regular schedule, it may be useful.

3. Don’t sweat the details.

There is evidence that data collected by sleep trackers can stress people out. It can add to anxiety and make insomnia worse. People become obsessed with the details, trying to explain every little blip in the data. If you find this is leading to obsessive behaviors for you, this could be a problem. Let it go. It may not be accurate anyway.

4. Corroborate the data with witness testimony.

There may be some inexplicable findings from your sleep tracker data. Perhaps some unremembered steps accumulated in the night. There may be frequent awakenings or restless sleep. The device may even report loud snoring. Try to verify these reports by asking a witness: consider questioning a bed partner. Learn if you sleepwalk, restlessly toss in the night, or rattle the windows with snoring. If there is a discrepancy, consider gathering more information before jumping to any conclusions.

5. If you are not sleeping well, get help.

Many people use sleep trackers because they are not sleeping well. They are hopeful that they may learn a little bit about why they are having difficulty sleeping. If the insomnia persists, this search can become desperate. Although some insight may be gleaned, more evaluation may be necessary. If you have poor sleep, especially if you have trouble sleeping through the night with frequent awakenings or experience daytime sleepiness, get evaluated by a board-certified sleep physician to sort out what might be contributing to your troubles.

Conclusion

It is fun to learn about ourselves. Sleep can be mysterious. Most of the night goes unremembered. It is natural to want to lift the curtain and glimpse a little about what occurs once our eyes close and we fall asleep. Be careful about positing too much faith into the accuracy of sleep trackers. The technology may improve with time, but these devices may be more novelties than serious scientific analyses. If you are struggling to sleep, get help from an expert.

How to Choose a Sleep Doctor

By Brandon Peters, MD

If you are having difficulties sleeping, you may need a referral to a sleep specialist, but how should you choose a sleep doctor? There are certain characteristics that you should consider when selecting a specialist so that you get the appropriate testing and help that you need.

Who is My Sleep Specialist?

There are many individuals who will be involved in your care if you seek treatment for a sleep disorder. You will likely start your evaluation with your primary health care provider. This may result in a referral to a sleep specialist, most often a physician but sometimes a midlevel provider such as a nurse practitioner or a physician’s assistant working under the supervision of a physician. There may be ancillary staff involved as well, including polysomnographic technologists who do the sleep studies.

Sleep Doctor Training

Physicians who are certified as sleep specialists have many years of education. To become a doctor they graduate from college with a four-year degree and attend four years of medical school. They then complete a medical residency and a fellowship in sleep medicine. Many specialists can pursue a sleep fellowship, including: pulmonologists, neurologists, psychiatrists, otolaryngologists (ear, nose and throat specialists) and even general practitioners in family medicine, pediatrics, or internal medicine. Some physicians may dabble in sleep medicine, even if they do not have formal board certification.

Finding a Specialist with Credentials

No matter the specialty training, it is advisable to seek out a physician who is certified with appropriate sleep medicine credentials from the American Board of Medical Specialties. This implies that your doctor’s education has been verified and that they have been able to pass a board examination that tests their knowledge of sleep medicine. If you are to undergo additional sleep testing, you may want to find a sleep center that with accreditation from the American Academy of Sleep Medicine.

Selecting an Appropriate Center

Finding a sleep specialist can be a little intimidating, but once you have found a reputable provider, you may want to evaluate whether he or she can meet your needs. You may rely on friends or family for recommendations. It is also important to consider how your condition may be evaluated. You will want to select a center that can provide a thorough and appropriate evaluation, including any necessary testing such as:

• Home sleep apnea testing

• Polysomnography

• Multiple sleep latency testing (MSLT)

As part of this consideration, you may need to take into account cost as well as your insurance coverage. The resources available to you are always expanding and with a little research you should be able to find a reputable sleep specialist to meet your needs.

What to Expect in a Sleep Study: A Comprehensive Guide

An in-center sleep study, also known as polysomnography, is a diagnostic test used to assess the quality and patterns of a person's sleep. It helps doctors evaluate sleep disorders such as obstructive sleep apnea (OSA), periodic limb movements of sleep (PLMS) associated with restless leg syndrome (RLS), narcolepsy, parasomnias, and other sleep-related conditions. Sleep studies are typically recommended when a patient experiences symptoms like excessive daytime sleepiness, loud snoring, choking during sleep, or difficulty falling and staying asleep.

If you’ve been advised to undergo a sleep study, it’s natural to feel a little anxious or uncertain about what to expect. While the process can seem intimidating at first, understanding the purpose, procedure, and how to prepare can help alleviate some of that stress. This article will walk you through what a sleep study entails, including the different types of studies, the preparation required, the procedure itself, and what happens afterward.

1. Why a Sleep Study Is Recommended

Sleep studies are recommended for a variety of reasons, typically when a sleep disorder is suspected but the symptoms cannot be fully understood through a simple medical history or a physical exam. Common conditions diagnosed through sleep studies include:

• Obstructive Sleep Apnea (OSA): Characterized by brief interruptions in breathing during sleep.

• Narcolepsy: A condition marked by sudden, uncontrollable sleep episodes during the day and fragmented sleep at night.

• Restless Leg Syndrome (RLS): An overwhelming urge to move the legs, often accompanied by discomfort and associated with periodic limb movements of sleep (PLMS).

• Periodic Limb Movement Disorder (PLMD): Characterized by involuntary leg movements (PLMS) during sleep that disturb sleep quality and may affect a bed partner.

• Insomnia: Persistent difficulty falling asleep or staying asleep.

• Parasomnias: Abnormal behaviors during sleep, such as sleepwalking or night terrors.

Sleep studies can also be used to monitor a person’s response to treatments or therapies, particularly for conditions like sleep apnea, where continuous positive airway pressure (CPAP) therapy may be used.

2. Types of Sleep Studies

There are different types of sleep studies based on the nature of the suspected sleep disorder and the environment in which the study takes place. The most common types include:

• Polysomnography (PSG): The most comprehensive sleep study, which involves monitoring a variety of physical parameters during sleep, including brain activity (EEG), heart rate (ECG), muscle activity (EMG), eye movements (EOG), oxygen levels (pulse oximetry), and airflow. This is usually conducted in a sleep center or hospital.

• Home Sleep Apnea Test (HSAT): A simplified version of the PSG that focuses on breathing and can be conducted in the comfort of your own home. This test is typically used to diagnose sleep apnea, particularly in patients who are suspected of having moderate to severe sleep apnea and do not have significant comorbid conditions. The test involves wearing sensors that track your breathing, oxygen levels, heart rate, and other variables while you sleep.

• Multiple Sleep Latency Test (MSLT): Used to diagnose narcolepsy and excessive daytime sleepiness (i.e., idiopathic hypersomnia), this test measures how quickly you fall asleep during several daytime naps.

Each of these studies provides valuable information, but the level of detail and the equipment used may differ based on your condition and the doctor’s recommendations.

3. Preparing for a Sleep Study

Proper preparation is key to ensuring the sleep study yields accurate and useful results. Here’s how you can prepare for your sleep study:

Before the Study

• Talk to Your Doctor: Your doctor will provide specific instructions based on your sleep study type. Follow all advice and disclose any medications or supplements you’re taking, as certain substances can affect sleep patterns. In many cases, you may be asked to avoid caffeine or alcohol before the study.

• Dress Comfortably: Wear loose, comfortable clothing to your appointment. You’ll be wearing the sensors, so tight or restrictive clothing isn’t necessary.

• Hair and Skin: The night before your sleep study, you may be asked to wash your hair thoroughly but avoid using any hair products such as gels, hairsprays, or oils. These can interfere with the electrodes and sensors. Make sure your skin is clean and free from oils, lotions, or makeup to ensure proper electrode adhesion.

• Arrive Early: You’ll typically be asked to arrive in the evening, usually between 7:00 PM and 9:00 PM, depending on the clinic’s schedule. This allows time for the technician to attach all the necessary sensors and equipment.

For Home Sleep Studies

If you're using a home sleep apnea test, your doctor will provide specific instructions on how to set up the equipment. The sensors will likely include a nasal cannula or sensor to monitor airflow, a pulse oximeter to track oxygen levels, and one or two belts to monitor chest and abdominal movements. You will be asked to wear the sensors overnight and return them the next morning for analysis.

4. What Happens During the Sleep Study?

A sleep study is typically conducted in a sleep center or clinic, where the environment is designed to replicate a normal bedroom setting while still allowing for close monitoring. Here’s a step-by-step breakdown of what to expect during the study:

Arrival at the Sleep Center

Once you arrive at the sleep center, you’ll be shown to a private room that resembles a hotel room. The room will usually have a comfortable bed, a bathroom, and the necessary equipment for the study. You may also be given a questionnaire to record any sleep-related notes or concerns.

Sensor Placement

A trained sleep technician will place electrodes and sensors on your body to monitor your sleep stages, brain activity, breathing, and other physiological data. These are typically attached as follows:

• EEG (electroencephalogram): Electrodes placed on your scalp to monitor brain activity.

• ECG (electrocardiogram): Electrodes placed on your chest to monitor heart rate and rhythm.

• EMG (electromyogram): Electrodes attached to your chin and legs to track muscle activity and movements.

• EOG (electrooculogram): Electrodes placed around your eyes to monitor eye movements.

• Pulse Oximeter: A small clip placed on your finger to measure blood oxygen levels.

• Chest and Abdominal Belts: To monitor your breathing and chest movements.

• Nasal Cannula: A small device placed under your nose to monitor airflow.

Although it may feel a bit uncomfortable at first, the technician will ensure everything is positioned correctly. The process of sensor placement usually takes around 30 minutes to an hour.

Sleeping During the Study

Once the sensors are in place, the technician will leave the room, and later you will be asked to go to sleep. The goal is to observe your natural sleep patterns, so you’ll be encouraged to sleep as you normally would at home. The technician will monitor you from another room, but they will be able to adjust the equipment and communicate with you if necessary. If needed, it is possible to use the restroom.

It may take some time to fall asleep due to the equipment, but many people eventually adapt to the sensations. The sensors are non-invasive, and while they can feel slightly restrictive, they are generally not painful.

Monitoring and Data Collection

As you sleep, the sensors will collect data on various parameters such as:

• Brain waves (sleep stages): Helping the doctor identify any disruptions in your sleep cycle.

• Heart rate and rhythm: To check for abnormalities.

• Breathing patterns: To identify interruptions in airflow or signs of sleep apnea.

• Leg movements: To check for conditions like periodic limb movement disorder or parasomnias.

The technician will continue to monitor your sleep throughout the night. If any issues arise, such as difficulty breathing or severe disruptions in sleep, the technician may adjust the equipment or wake you briefly to re-position things or to initiate treatment.

5. After the Sleep Study

Once the study is complete, typically in the morning, the technician will remove all the sensors, and you’ll be free to leave. If the sleep study is conducted in a clinic, you may be able to leave immediately after, or you may be asked to stay for a brief debriefing. If it’s a home study, you’ll return the equipment the next day.

The data from the study will be analyzed by a board-certified sleep specialist or a doctor. Depending on the findings, your doctor may diagnose you with a sleep disorder or recommend further tests or treatments.

6. Results and Next Steps

After the sleep study, the results are typically available within a week or two. Your doctor will review the data and schedule a follow-up appointment to discuss the findings, which may be delayed further depending on availability. Based on the results, possible next steps may include:

• Diagnosis of a Sleep Disorder: If a disorder like sleep apnea, PLMD, parasomnias, or narcolepsy is diagnosed, the doctor will discuss treatment options, including lifestyle changes, CPAP therapy, medications, or referrals to specialists.

• Further Testing: In some cases, such as with an inconclusive result, additional tests may be necessary for a more comprehensive diagnosis.

• Treatment Recommendations: For conditions like sleep apnea, you may be fitted for a CPAP machine or other devices to improve breathing during sleep.

Conclusion

A sleep study can seem intimidating, but it is a safe and effective way to diagnose sleep disorders. By understanding what to expect, you can enter the study feeling prepared and more at ease. Whether you’re undergoing a comprehensive polysomnography in a sleep center or using a home sleep apnea test, the process is designed to provide critical information that will help your doctor assess your sleep patterns and recommend appropriate treatment options. By diagnosing and addressing sleep disorders, sleep studies can significantly improve your quality of life, leading to better rest and overall health.

This article was created using OpenAI’s ChatGPT on December 2, 2024 and it was personally reviewed and edited by Brandon Peters, M.D. to ensure its accuracy. This use of augmented intelligence in this way allows the creation of health information that can be trusted.

What Is the Definition of Apnea-Hypopnea Index (AHI)?

The apnea-hypopnea index (AHI) is a critical measurement used in the diagnosis and assessment of sleep apnea, a disorder characterized by repeated interruptions in breathing during sleep. Understanding AHI is essential for both patients and healthcare providers, as it helps to determine the severity of sleep apnea and guide treatment decisions. This article will explore the definition of the AHI, its calculation, significance, and implications for patient management.

Definition of Apnea-Hypopnea Index (AHI)

The apnea-hypopnea index is defined as the total number of apnea and hypopnea events experienced per hour of sleep. An apnea event is a complete cessation of airflow for at least 10 seconds, while a hypopnea refers to a partial blockage of airflow that results in a 30% or more reduction in airflow and is often accompanied by a drop in blood oxygen levels or arousal from sleep. The AHI provides a quantifiable measure of the severity of sleep-disordered breathing, making it a crucial tool in sleep medicine.

Calculation of AHI

The AHI is often calculated using data collected during an in-center sleep study, known as a polysomnogram (PSG). During this study, various physiological parameters are monitored, including:

• Airflow: Measured through nasal and oral airflow sensors.

• Oxygen Saturation: Monitored via pulse oximetry to assess blood oxygen levels.

• Respiratory Effort: Evaluated through sensors placed around the chest and abdomen to measure movements during breathing.

• Sleep Stages: Identified to understand the patient’s overall sleep architecture.

The formula for calculating the AHI is straightforward:

For example, if a patient experiences 30 apneas and 40 hypopneas during a 6-hour sleep study, the AHI would be calculated as follows:

This means the patient has approximately 11.67 events per hour of sleep.

Interpretation of AHI Values

The AHI is essential for classifying the severity of sleep apnea and guiding treatment. The values are typically interpreted as follows:

• Normal: AHI < 5

• Mild Sleep Apnea: AHI 5-14.9

• Moderate Sleep Apnea: AHI 15-29.9

• Severe Sleep Apnea: AHI 30 and higher

These categories help healthcare providers determine the appropriate interventions, ranging from lifestyle changes and continuous positive airway pressure (CPAP) therapy to surgical options.

Significance of AHI

1. Assessment of Severity: The AHI serves as a standardized measure to assess the severity of sleep apnea. By quantifying the frequency of apneas and hypopneas, clinicians can better understand the extent of the disorder and its impact on the patient’s health.

2. Risk Stratification: Higher AHI values are associated with an increased risk of cardiovascular diseases, metabolic disorders, and other health complications. Understanding a patient’s AHI helps healthcare providers stratify risk and develop comprehensive management plans.

3. Treatment Monitoring: AHI is also valuable for monitoring the effectiveness of treatment. For instance, patients using CPAP therapy will have reports from their device on whether the treatment is effectively reducing sleep-disordered breathing events.

4. Guiding Patient Management: The AHI can inform decisions regarding lifestyle modifications, such as weight loss or positional therapy, as well as the need for more aggressive interventions. For example, patients with moderate to severe AHI may require CPAP therapy or other treatments more urgently than those with mild sleep apnea.

5. Patient Education: Understanding AHI can empower patients to take an active role in their health management. By knowing their AHI values and the implications for their health, patients can be more motivated to adhere to treatment plans and make necessary lifestyle changes.

Limitations of AHI

While the AHI is a valuable metric, it is essential to recognize its limitations:

• Not a Comprehensive Measure: The AHI focuses solely on the frequency of apneas and hypopneas and does not account for their duration or impact on sleep quality. For instance, a patient with a high AHI may have frequent short events, while longer events may lead to greater drops in the blood oxygen levels.

• Variability Among Individuals: Individual responses to sleep apnea can vary. Some patients may experience severe health consequences with a relatively low AHI, while others may have a high AHI without significant daytime symptoms. This variability highlights the importance of considering additional factors, such as patient history and comorbid conditions, when assessing sleep apnea severity.

• Subjectivity in Scoring: The classification of apneas and hypopneas can be somewhat subjective and may vary based on the criteria used by different sleep laboratories. Variations in scoring can lead to discrepancies in AHI calculations, potentially impacting diagnosis and treatment decisions.

• Need for Comprehensive Evaluation: AHI is just one component of a complete sleep evaluation. A thorough assessment should include a review of symptoms, medical history, and physical examination to develop a comprehensive understanding of the patient's condition.

Conclusion

The apnea-hypopnea index (AHI) is a critical measurement in sleep medicine that quantifies the frequency of apneas and hypopneas per hour of sleep. By providing a standardized assessment of sleep-disordered breathing severity, the AHI plays a vital role in diagnosing and managing sleep apnea. Understanding AHI values can help healthcare providers stratify risk, monitor treatment effectiveness, and guide patient management. However, it is essential to consider the limitations of AHI as part of a comprehensive evaluation of sleep apnea, ensuring that all relevant factors are taken into account for effective diagnosis and treatment. With awareness of AHI and its implications, patients can engage more actively in their healthcare journey and work towards better sleep and overall health.

This article was created using OpenAI’s ChatGPT on August 2, 2024 and it was personally reviewed and edited by Brandon Peters, M.D. to ensure its accuracy. This use of augmented intelligence in this way allows the creation of health information that can be trusted.