Summary
Registered dietitians Briarley Horton and Carolyn Williams discuss seasonal affective disorder (SAD) in a conversational, practical episode. They reveal that SAD symptoms can begin as early as October and worsen around the end of daylight saving time, with January and February being the peak months -- meaning SAD can span a full five months. Both hosts share personal experiences with seasonal depression, with Carolyn noting a dramatic mood improvement after moving from Vermont to the southern United States. The hosts walk through SAD symptoms including sadness, irritability, carb cravings, loss of interest, sleep changes, difficulty concentrating, and weight changes. They highlight fatigue as the most commonly missed early symptom, since people easily rationalize low energy as normal winter behavior. Risk factors include being female, family history, living further from the equator, and having existing mental health conditions like major depressive disorder or bipolar II. Their five actionable strategies include using a 10,000 lux light box for 20-30 minutes within the first hour of waking, considering proactive antidepressant treatment before symptoms peak, lining up therapy appointments, maintaining an exercise routine (citing a study showing running 2-3 times weekly matched antidepressant effectiveness at 43-44% remission rates), and supplementing with vitamin D3 at 1,000-2,000 IU daily to support serotonin production and circadian rhythm regulation.
Key Points
- SAD symptoms can start as early as October and span five months, with peak severity in January and February
- Fatigue is the most commonly missed early symptom of SAD because people rationalize it as normal winter tiredness
- SAD is more common in women, people with family history, those living far from the equator, and those with existing depression or bipolar disorder
- A 10,000 lux light box used for 20-30 minutes within the first hour of waking is a research-supported treatment for SAD
- A study of 140 people found group running 2-3 times per week for 16 weeks matched antidepressant effectiveness (43% vs 44% remission), with additional physical health benefits
- Proactive treatment is key -- start antidepressants or therapy before SAD season peaks, not after symptoms are already severe
- Vitamin D3 supplementation at 1,000-2,000 IU daily supports serotonin production and may reduce SAD risk, since low vitamin D increases susceptibility
- Exercising outdoors during daylight hours provides a double benefit by combining movement with natural light exposure
Key Moments
SAD symptoms can start as early as October
The hosts reveal the surprising statistic that seasonal affective disorder symptoms can begin in October, much earlier than most people expect, with symptoms worsening around the end of daylight saving time and peaking in January and February.
"Symptoms start in October. Yes, we are actually well into seasonal affective disorder season."
Fatigue is the most commonly missed early symptom of SAD
Experts identify fatigue as the number one early symptom of SAD that most people miss, because it is so easy to rationalize as normal winter behavior like wanting to stay in when it is cold and dark outside.
"But there's one symptom you didn't miss, you didn't mention. Yes. So this one, this is like the number one, like what experts think is the most common early symptom of SAD that most people miss. Okay. Because it's an early symptom. What is it? Fatigue."
Light box therapy protocol for SAD
The hosts share the recommended protocol for light box therapy: exposure of 10,000 lux that emits minimal UV light, used within the first hour of waking for 20 to 30 minutes each morning.
"am I wasting my money or is this legit? Yeah. So what did you find? So the recommendation is an exposure of 10,000 lux of light and emit as little UV light as possible. I mean, I guess, cause you don't, you know, UV light can be harmful. And then you want to use this light box within the first hour of waking up in the morning for about 20 to 30 minutes. That's the recommendation."
Running matched antidepressants for depression remission
A study comparing running to antidepressants found nearly identical remission rates (43% for runners vs 44% for medication), with runners also seeing improvements in weight, lung function, and blood pressure.
"Both groups had very similar improvements in their symptoms. 43% of the runners saw their depression go into remission, and 44% of the antidepressant group went into remission."
