Seasonal Energy Changes: What to Track

You felt unstoppable in June. Waking up energized, productive all day, sleeping soundly at night. Now it's January, and you can barely drag yourself out of bed. What changed?

The seasons did. And your energy inputs need to change with them.

Most people treat energy as a static equation: same sleep, same food, same movement should equal same energy. But your body doesn't work that way. It responds to light, temperature, and environmental cues that shift dramatically throughout the year.

The solution isn't to fight seasonal changes—it's to track them and adapt your inputs accordingly.

Why Seasons Affect Your Energy

Your body runs on circadian rhythms—internal clocks that regulate sleep, alertness, hormone release, and energy. These rhythms are calibrated primarily by light exposure.

In summer:

• Longer daylight hours signal your body to stay awake longer
• Morning light comes earlier, making waking easier
• More natural light exposure throughout the day
• Temperature encourages outdoor activity

In winter:

• Shorter days confuse your circadian rhythm
• Dark mornings make waking feel unnatural
• Limited light exposure during work hours
• Cold temperatures reduce outdoor activity motivation

Key Insight: Your energy isn't failing in winter—it's responding to different environmental inputs. Track what you control, then adjust for the season.

This isn't about seasonal affective disorder (though that's real and treatable). This is about the normal, predictable energy shifts that affect everyone when environmental conditions change.

The Core Seasonal Inputs to Track

1. Light Exposure

Light is the master circadian regulator. In summer, you get it naturally. In winter, you need to be intentional.

What to track:

• Morning light exposure (time and duration)
• Total outdoor time during daylight hours
• Use of light therapy or bright indoor lights
• Evening light exposure (screens, bright rooms)

Season	Morning Light Challenge	Afternoon Light Challenge
Summer	Often too early (pre-alarm)	Abundant—often no issue
Winter	Dark at wake time	Sunset during work hours
Spring/Fall	Variable—weather dependent	Shortening or lengthening days

Light affects:

• Wake-up alertness
• Daytime energy levels
• Sleep timing and quality
• Mood and motivation

For most people, winter energy problems trace back to insufficient light exposure. Your body literally doesn't know it's daytime.

2. Sleep Timing Shifts

Your natural sleep timing changes with seasons. Fighting this creates energy problems.

What happens:

• Summer: Natural tendency to stay up later, wake earlier
• Winter: Natural tendency to sleep longer, wake later

What to track:

• Natural bedtime urge (when you feel sleepy)
• Natural wake time (without alarm, on weekends)
• Sleep opportunity you're giving yourself
• Time in bed vs. hours needed by season

Some people need 30-60 minutes more sleep in winter. If you're giving yourself summer sleep hours in January, you're starting every day in debt.

3. Activity Level Changes

Movement creates energy, but seasonal barriers affect how much you move.

Summer movement:

• Walking is pleasant
• Outdoor activities are accessible
• Natural inclination to be active
• Light evenings encourage after-work activity

Winter movement:

• Cold reduces outdoor motivation
• Dark mornings/evenings limit options
• Holiday disruptions break routines
• Indoor exercise requires more planning

What to track:

• Daily movement type and duration
• Outdoor vs. indoor activity
• Movement-energy connection patterns
• Missed movement days and reasons

The data often reveals that winter energy drops correlate directly with reduced movement—a controllable input, not an inevitable seasonal fate.

4. Temperature and Environment

Your body expends energy regulating temperature, and your environment affects energy levels directly.

What to track:

• Indoor temperature (home and work)
• Outdoor exposure time
• Cold-related energy drain
• Heating effects on air quality/hydration

Cold environments require energy to maintain body temperature. Hot, dry indoor heating dehydrates you. Both affect energy levels.

Seasonal Input Adjustments

Winter Energy Strategy

Winter challenges energy on multiple fronts. Here's what to adjust:

Light:

• Get outside within 60 minutes of waking, even briefly
• Consider a 10,000-lux light box for morning use
• Take midday walks during lunch break (peak daylight)
• Dim evening lights earlier to support earlier sleep

Sleep:

• Allow 30-60 minutes more sleep opportunity
• Accept earlier bedtime as natural
• Maintain consistent wake time despite darkness
• Track whether you need more sleep or just feel like you do

Movement:

• Plan indoor alternatives before winter hits
• Schedule movement like meetings—non-negotiable
• Use the morning energy tracking approach to find optimal exercise timing
• Even 10-minute indoor movement counts

Food:

• Watch for comfort food patterns that tank energy
• Track meal timing as days shorten
• Ensure adequate vitamin D (discuss with your doctor)
• Hydration matters even when you're not sweating

Summer Energy Strategy

Summer seems easier, but has its own challenges:

Light:

• Morning light might wake you too early
• Evening light can delay bedtime
• Consider blackout curtains for sleep
• Track whether late summer evenings hurt next-day energy

Sleep:

• Resist staying up late just because it's light
• Maintain consistent bedtime despite daylight
• Watch for social schedule disruption
• Track sleep consistency even in relaxed summer

Movement:

• Heat can be as limiting as cold
• Early morning or evening exercise in extreme heat
• Track hydration needs in higher temperatures
• Don't assume outdoor time equals quality movement

Food:

• Appetite often decreases in heat
• Under-eating can cause energy crashes
• Track whether summer eating patterns affect energy
• Hydration becomes critical

Transition Season Strategy (Spring/Fall)

The weeks around solstice transitions cause the most disruption:

Track:

• When you notice energy shifts
• How long adjustment takes
• Which inputs need changing first
• What worked in previous transitions

Spring and fall require attention to rapidly changing conditions. What worked last week might not work this week as daylight shifts by minutes daily.

Building Your Seasonal Tracking System

Start with Light

Light exposure is the highest-leverage seasonal input. Track it first.

Simple approach:

• Log morning outdoor time (even 5 minutes counts)
• Note total daylight exposure
• Track energy levels

Look for:

• Correlation between morning light and energy
• Impact of midday outdoor breaks
• Difference between work-from-home and office days

Layer in Sleep Adjustments

Once you understand your light patterns, track sleep seasonally.

Questions to answer:

• Do you need more sleep in winter?
• Does your natural bedtime shift?
• How does light exposure affect sleep timing?
• What's your ideal sleep baseline in each season?

Connect to Movement

Movement patterns often explain seasonal energy shifts better than any other factor.

Track:

• Movement frequency across seasons
• Indoor vs. outdoor activity
• Movement timing changes
• How movement correlates with energy in different seasons

Patterns to Watch For

After tracking across seasons, you'll likely discover:

The Winter Light Pattern

Many people find that adequate morning light (natural or artificial) can prevent most winter energy decline. Ten minutes of outdoor light before 9am might matter more than any supplement or sleep adjustment.

The Sleep Duration Shift

Some people genuinely need more sleep in winter—their data shows better energy with 8+ hours vs. their summer 7-hour baseline. Others find they just feel like they need more sleep but function fine on the same amount if they get sufficient light.

The Movement Drop Effect

Energy often tracks movement more than it tracks season. A winter with maintained activity can feel as energetic as summer. The energy experiments you run will reveal your personal pattern.

The Compound Effect

Seasonal energy problems are usually compound: less light + less movement + more comfort food + irregular sleep = significant energy decline. Fixing any single input helps, but addressing the combination transforms winter energy.

What Your Data Reveals

After tracking through a full seasonal cycle, you'll know:

Your seasonal sleep needs:

• Do you genuinely need more winter sleep?
• What bedtime shift works best?
• How does light exposure change sleep timing?

Your light threshold:

• How much morning light prevents energy decline?
• Does artificial light work as well as natural?
• When do you need to start winter light strategies?

Your movement-energy relationship:

• How much does reduced movement affect your energy?
• What indoor alternatives work for you?
• Can exercise compensate for less light?

Your personal adjustment timeline:

• When do you need to start seasonal changes?
• How long does adjustment take?
• What's your early warning sign that inputs need shifting?

Common Mistakes

Blaming the Season, Not Tracking Inputs

"Winter makes me tired" isn't actionable. "I get 40 minutes less light and move 50% less in winter" tells you exactly what to change.

Using Last Year's Strategy Without Data

What worked last winter might not work this winter. Your life changes. Track fresh each year.

Waiting for Problems Before Adjusting

By the time your energy crashes, you're playing catch-up. Start seasonal adjustments as inputs change, not after outcomes suffer.

Fighting Your Biology Instead of Working With It

If your body wants to sleep earlier in winter, fighting it costs energy. Sometimes adaptation means accepting seasonal shifts rather than maintaining artificial consistency.

The Trendwell Approach

Seasonal energy changes aren't a problem to fix—they're a pattern to work with.

Track your inputs across seasons:

• Light exposure timing and duration
• Sleep opportunity and timing
• Movement type and frequency
• Environmental factors

Find your correlations, then adjust inputs proactively as seasons change. The goal isn't to feel the same year-round—it's to optimize energy for each season's reality.

Next Steps

• Start tracking morning light exposure and outdoor time today
• Note your current energy baseline before the next seasonal shift
• Review your movement patterns—are they seasonal?
• Identify which season historically challenges your energy most
• Plan one input adjustment to test this season
• Read: Finding Your Energy Baseline to establish your personal patterns
• Read: Running Energy Experiments to test seasonal strategies

Your energy isn't at the mercy of the seasons. It's at the mercy of inputs that happen to change with seasons. Track those inputs, adjust proactively, and maintain energy year-round.

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Last updated: January 2026