Controlled study
Short sleep, hormones and hunger: the Spiegel experiment
In a crossover experiment involving 12 young men, restricted sleep was associated with 18% lower leptin, 28% higher ghrelin and 24% greater subjective hunger than sleep extension.
- Evidence design
- Randomized crossover clinical trial
- Population and methods
- Original extraction in Portuguese is available in the study details.
- Assessment period
- After two days in each experimental condition
- Reported units
- % relative difference
Keep in view
- Only 12 young men, with two two-day conditions; not representative of all populations.
- It does not establish future weight gain or a universal hormonal pattern.
See study details — Sleep restriction experiment
Study design and methods
Randomized crossover clinical trial
Original extraction (Portuguese)
População
Homens jovens saudáveis; idade média 22 anos e IMC médio 23,6 kg/m².
- Study design
- Ensaio cruzado randomizado com duas condições de dois dias; ingestão calórica e atividade controladas.
- Reported sample count
- 12
- Role of the reported sample count
- Reported study sample; not necessarily the denominator for each outcome
- Included study count
- 1
- Role of the study count
- Single study
- Research question
- A restrição parcial do sono altera hormônios relacionados ao apetite e a fome percebida?
- Qualified findings
- Neste pequeno experimento, o período de sono restrito apresentou menor leptina, maior grelina e maior fome/apetite do que a extensão. O resultado oferece evidência experimental de curto prazo, sem estabelecer padrão hormonal universal.
- Estimand and analysis rules
- Not reported or not verified
- Reason the formal estimand is unavailable
- A complete formal estimand was not extracted from the verified input.
Extracted outcomes
| Outcome and group | Reported value | Assessment period | Sample and denominators | Uncertainty |
|---|---|---|---|---|
| Mean leptin Sleep restriction versus extension Effect estimate | -18 % relative difference reported relative difference Unit: % relative difference | After two days in each experimental condition | Reported N: 12 — unique crossover-study participants; not an outcome-specific denominator
| CI not supplied in the verified scope. Reported p-value: 0.04 (between condition comparison) |
| Mean ghrelin Sleep restriction versus extension Effect estimate | 28 % relative difference reported relative difference Unit: % relative difference | After two days in each experimental condition | Reported N: 12 — unique crossover-study participants; not an outcome-specific denominator
| CI not supplied in the verified scope. Reported p-value: <0.04 (between condition comparison) |
| Subjective hunger Sleep restriction versus extension Effect estimate | 24 % relative difference reported relative difference Unit: % relative difference | After two days in each experimental condition | Reported N: 12 — unique crossover-study participants; not an outcome-specific denominator
| CI not supplied in the verified scope. Reported p-value: <0.01 (between condition comparison) |
Mean leptin — Sleep restriction versus extension: extraction context
- Outcome role
- Not specified in the consulted scope
- Scale reference
- relative_to_sleep_extension_condition
- Extraction location
- Original article abstract
- The same participants experienced both conditions; do not count them as 24 people.
Mean ghrelin — Sleep restriction versus extension: extraction context
- Outcome role
- Not specified in the consulted scope
- Scale reference
- relative_to_sleep_extension_condition
- Extraction location
- Original article abstract
- The same participants experienced both conditions; do not count them as 24 people.
Subjective hunger — Sleep restriction versus extension: extraction context
- Outcome role
- Not specified in the consulted scope
- Scale reference
- relative_to_sleep_extension_condition
- Extraction location
- Original article abstract
- The same participants experienced both conditions; do not count them as 24 people.
What the curated evidence supports
- In a crossover experiment involving 12 young men, restricted sleep was associated with 18% lower leptin, 28% higher ghrelin and 24% greater subjective hunger than sleep extension.
Limitations
- Only 12 young men, with two two-day conditions; not representative of all populations.
- It does not establish future weight gain or a universal hormonal pattern.
Verification scope
Verified through 2026-11-04 within the consulted scope.
- Bibliographic metadata checked
- Yes
- Original article abstract consulted
- Yes
- Full-text consultation
- Not consulted
- full text verified fields
- Official trial registry consulted
- No
- Statistical analysis plan consulted
- No
- Verification boundary
- Verification is limited to the input's identified abstract/full-text fields. A trial identifier linked by an article does not imply a separate registry review.
Source record
Brief communication: Sleep curtailment in healthy young men is associated with decreased leptin levels, elevated ghrelin levels, and increased hunger and appetite (2004)